[Treatment] DNA
Gene therapy is integrated with normal genes into cells, correction and replacement genes that cause a method of treatment. Currently Broadly speaking, some will be transferred to patients with genetic material within cells to play a role in order to achieve purpose of treating disease, also referred to as gene therapy.
At present gene therapy, the method used can basically be divided into the following types:
1 DNA Correction
Correction DNA chain refers to the abnormal pathogenic DNA base rectify normal part be retained.
2. DNA replacement
DNA replacement is to use the normal DNA in vivo DNA through homologous recombination, in situ lesions replacement pathogenic DNA in the cell, the DNA within the cells fully restored to normal conditions.
3. Added DNA
DNA will be added to that purpose of DNA into cells or other cells lesion, removing abnormal DNA, but through DNA purpose of the non-site-specific integration, and expression of compensation to the function of DNA defects or to the original function has been strengthened. At present DNA treatment of multiple use of such methods. This method is added to the more dominant DNA for the treatment of recessive disease.
4. DNA inactivation
Early generally refers antisense oligonucleotide technology. It is a specific antisense RNA, including antisense RNA, antisense and ribozymes DNA into cells, the level of transcription and translation in blocking the abnormal expression of certain genes. In recent years have anti-gene strategy, peptide nucleic acid, DNA and RNA interference removed.
[DNA is the genetic material of all living organisms - the basis of
DNA (deoxyribonucleic acid) is a class of nucleic acid, containing elements for deoxyribose named.
Very large DNA molecules (molecular weight, at least in general over 1 million), the main component is deoxynucleotidyl adenine, guanine deoxynucleotidyl, cytosine and thymine deoxynucleotidyl deoxynucleotidyl. DNA exists in the nucleus, mitochondria and chloroplasts, can also exist in the free state of certain cell cytoplasm. Most of the known phage, some animal virus and a handful of plant viruses also contain DNA.
In addition to RNA (ribonucleic acid) and phage, DNA is the genetic material of all living organisms basis. The similarity between organisms paternity and inheritance of the so-called genetic information, stored in the DNA molecule. 1953, Danmushiwosen and Francis Crick describe the structure of DNA: the one-to-many mutual coiled chain nucleotide composition of the double helix. Thus, they are with the London Institute of Technology physicist Frederick countries Keweierjinshi shared the 1962 Nobel Prize in Physiology or Medicine.
[Obese gene]
Royal London Hospital scientists found that in obese body, there is a unique function of the gene, the gene of the three colleagues in the chromosome. As the obesity gene exists only in the body, therefore, the scientists called "obesity gene."
The study found that obese gene to the body to create a transport fat in the blood protein - "APO-D" gene. The gene more fat more fluent in blood circulation, the accumulation of fat in the more people will be obese. Below scientists conducted an interesting experiment: Let a portable mouse obese gene mating results and future generations of each roller melon circular slip become a meat ball, and did not allow a mouse obese gene mating, production of less fat mice, each very emaciated. Genetic scientists in accordance with this model, but also produce free of fat in 20 ~ 50% of the mice Feishou varying degrees. Further found that the obese gene and rodent genetic situation is somewhat different, are generational genetic. That is, people can observe, and to a considerable number of families, fat grandmother general obesity gene will not be passed to their children, but to her grandchildren were. The scientists also found that obesity-related genes more than one. For example, New York's Rockefeller University, a research team recently announced that they After eight years of long study, found a can control appetite and energy metabolism genes. It is reported that the gene can be sent to the brain to stop eating a signal to the brain's master timely weakened appetite, in order to avoid excess energy if the gene variation, the master will increase appetite, Tanzui eat, and eventually become a big fat. Further study revealed that the gene from the 4500 base composition, some of which can produce from 167 amino acid composition of proteins. If this protein synthesis normal, we will be able to stop eating the brain that signal if the encoded protein encoded amino acid composition of the first 105 amino acid residues of the unusual base, the signal to stop eating will malfunction, resulting in obesity.
Monday, April 21, 2008
DNA probe
DNA probe
DNA probe is the most commonly used DNA probe that several hundred base pairs in length more than double-stranded DNA or single chain DNA probe. DNA probe has been the large number, there are bacteria, viruses, protozoa, fungi, animals and human cell DNA probe. Such probes for more than a gene sequence in whole or in part, or a non-coding sequences. These DNA fragments should be a specific, such as bacterial virulence factor gene probes and human Alu probe. These DNA probes depends on access to the molecular cloning technology development and application. Bacteria for example, molecular hybridization technology for bacterial strain identification and classification than the percentage of the value of G + C to accurate, is a bacterial taxonomy development direction. In addition elements of the high sensitivity of hybridization, molecular hybridization in the diagnosis of clinical microbiology has broad prospects. Bacterial genome size of approximately 5 × 106bp, containing about 3,000 genes. Between the vast majority of bacterial DNA is the same, in order to get a specific nucleic acid probe bacteria, usually to build a library of bacterial genomic DNA approach will be of bacterial DNA into small fragments were cloned after the genome contains all the information Cloning library. Then use a variety of other bacteria's DNA as a probe to screen a hybridization signal Cloning been removed, the last remaining non-hybrid with any other bacterial cloning may contain the bacteria specific DNA fragment. This recombinant plasmid probe after further identification markings can be identified by DNA sequence analysis of their genetic origin and function. So to be a specific DNA probe is more often tedious. Cloning DNA probe can be applied in the screening serology, as well as the different DNA library is built for the expression of cloned colony or plaque after the release by cracking antigen expression, and then use the source of bacteria polyclonal antiserum screening positive clones , which has a number of positive clones by other bacteria to the anti-serum screening, but only with the response of serum anti-bacterial expression of this bacterial clones that contain specific gene fragment, it is the protein encoded by specific bacteria. Use this expression library by screening apparently just specific gene probe.
DNA repair
DNA repair (DNA repairing) cell DNA damage by the response, this response may resume DNA structure as it is, can re-implementation of its original function, but sometimes are not able to completely eliminate the DNA damage, but cells This tolerance to DNA damage and can continue to survive. Perhaps this has not fully repair the damage and hold down the right conditions will be shown under (such as of cancerous cells, etc.), but if the cells do not have this repair, it is impossible to deal with the frequent occurrence of DNA damage in the incident, survival . Therefore DNA repair research is to explore an important aspect of life, but also with military medicine, oncology, and other closely related. On the different DNA damage, cells can have different repair responses. DNA contains A, C, G and T four bases, under normal circumstances A - T, C - G base pairs combination of a DNA cross-linked files. Interpretation of DNA genes is through these bases in order to convey instructions to the cells, control cells work. Many factors could cause DNA strand breaks, DNA chain in the reorganization to rearrange the base, resulting in the interpretation of the original base sequences and different, send the wrong instructions, resulting in the wrong cell growth and working conditions, variation in the cell, also will have the tumor cells. Tumor cells will absorb a large amount of nutrients or normal human cells grow rapidly, tumor cells than normal cells much larger nucleus than the normal 1-5 times, and more deformed, and so on. At the same time tumor DNA chain in the same situation will be broken, because DNA repair and half with its own reservations about the function of reproduction, DNA ligase can be linked to DNA fragment again in the next rotation of the role of re-forming spiral. And a small section of genetic DNA of tumor cells can generate new characteristics of tumor cells. Now scientists are often referred to cloning, the DNA is the use of this property. So most of the tumor DNA chain reorganization is a change of two or more of a change process, which form the tumor cell replication and propagation, which resulted in tumor expansion, proliferation, transfer and deterioration, and ultimately threaten human health and life.
[DNA replication:
DNA replication is double-stranded DNA prior to cell division in the replication process, the result is copied into a double strand of the double-stranded two different (if the normal process of reproduction), with each double-strand of the double-stranded, like the original . This process is called semi-through replication mechanism to retain the smooth completion. Copy can be divided into the following phases:
Start-up phase: gyrase in local start the double helix structure of DNA molecules a single chain of primers to identify the start bit, in order to solve the section of DNA as a template, according to the 5 'to 3' direction of short-chain RNA synthesis. Forming RNA primer.
DNA fragments generated: provide a primer 3'-OH ends on the basis of DNA polymerase chain of the two catalytic DNA replication process at the same time, because the process can only be copied from the 5'-> 3 'direction synthesis, a chain to continuous synthesis, a separate chain of subparagraph, each of which became a short chain Okazaki fragment (Okazaki fragments).
RNA hydrolysis primer: When a certain length of DNA synthesis, DNA polymerase hydrolysis of RNA primer, Buchen gap.
DNA ligase DNA fragments will phosphate ester bond of linking it to a complete DNA molecule.
Finally new synthetic fragments of DNA gyrase help in the re-formation of spiral.
[Single-strand DNA]
Single-stranded DNA (single-stranded DNA) to the majority of the double helix structure of DNA exist, but the heat or alkaline treatment will be linked into a single state. Single-strand DNA refers to the existence of this state of the DNA. Single strand DNA molecules in the fluid mechanics nature, absorption spectra, base response nature of both double-stranded DNA and different. Certain phage particles containing single-chain ring of DNA, the phage DNA in the cell proliferation when a double-stranded DNA.
Closed-loop [DNA]
Closed-loop DNA (closed circular DNA) did not fracture of the double-stranded circular DNA, which is also known as super-helical DNA. Due to the double-stranded helical structure of their closure, with the result that the entire DNA molecule further spin-formed three-tier structure. If another one or two different parts of the chain have a fracture, it will become a Rotary song open-loop DNA molecule. Extracted from the cells in the plasmid or viral DNA contains the closed-loop and open-loop that two kinds of molecules. According to the two pigment can be combined with the ability of different, and both will be separated from.
DNA [link]
DNA link (Linker DNA): nuclear body, in addition to 146 bp DNA, the core of all DNA.
[Template DNA]
Template DNA can be single-chain molecule, it can also be a double-stranded molecule, it could be linear elements, it can also be a cyclic molecules (molecular ratio ring linear amplification effect of a lesser extent). On the template DNA, PCR impact The main factor is the number of templates and purity.
[Complementary DNA]
Complementary DNA (cDNA, complementary DNA) gene of a double-stranded DNA molecule with a single chain as a template, the transcription produce its sequence complementary messenger RNA molecules, and then the role of reverse transcriptase, to mRNA molecules as templates, and a Synthesis mRNA sequence complementary single strand DNA, and finally a single-stranded DNA as a template synthesis another one with the complementary single strand DNA, the two complementary single strand DNA molecules to form a double-stranded cDNA molecule. Therefore, the double-stranded cDNA sequence elements with the mRNA transcription of the gene is the same. therefore a cDNA molecule on behalf of a gene. cDNA but still different from the genes, because a gene mRNA transcription, coding some of the intron sequence that was deleted, retained only the coding sequence, that is, Exon. cDNA sequence than it should be much shorter sequence, because cDNA gene are not included in the non-coding sequences - intron.
[DNA restriction fragment length polymorphism analysis:
In the human genome, an average of about 200 pairs a base mutation can occur (known as the neutral mutations), neutral mutations lead to inter-individual differences in nucleotide sequence, known as DNA polymorphism. Many polymorphisms in DNA restriction enzyme recognition site, the enzyme DNA fragment length will be a different fragment, known as restriction fragment length polymorphism (RFLP). RFLR way by Mendelian genetics, in a particular family, and if a disease-specific gene fragment polymorphism closely linked polymorphic fragments that can be used as a kind of "genetic markers" to family members or judgement whether fetal genes that cause carriers. A hemophilia, cystic fibrosis and phenylketonuria, and other lesions can be diagnosed using this method.
DNA probe is the most commonly used DNA probe that several hundred base pairs in length more than double-stranded DNA or single chain DNA probe. DNA probe has been the large number, there are bacteria, viruses, protozoa, fungi, animals and human cell DNA probe. Such probes for more than a gene sequence in whole or in part, or a non-coding sequences. These DNA fragments should be a specific, such as bacterial virulence factor gene probes and human Alu probe. These DNA probes depends on access to the molecular cloning technology development and application. Bacteria for example, molecular hybridization technology for bacterial strain identification and classification than the percentage of the value of G + C to accurate, is a bacterial taxonomy development direction. In addition elements of the high sensitivity of hybridization, molecular hybridization in the diagnosis of clinical microbiology has broad prospects. Bacterial genome size of approximately 5 × 106bp, containing about 3,000 genes. Between the vast majority of bacterial DNA is the same, in order to get a specific nucleic acid probe bacteria, usually to build a library of bacterial genomic DNA approach will be of bacterial DNA into small fragments were cloned after the genome contains all the information Cloning library. Then use a variety of other bacteria's DNA as a probe to screen a hybridization signal Cloning been removed, the last remaining non-hybrid with any other bacterial cloning may contain the bacteria specific DNA fragment. This recombinant plasmid probe after further identification markings can be identified by DNA sequence analysis of their genetic origin and function. So to be a specific DNA probe is more often tedious. Cloning DNA probe can be applied in the screening serology, as well as the different DNA library is built for the expression of cloned colony or plaque after the release by cracking antigen expression, and then use the source of bacteria polyclonal antiserum screening positive clones , which has a number of positive clones by other bacteria to the anti-serum screening, but only with the response of serum anti-bacterial expression of this bacterial clones that contain specific gene fragment, it is the protein encoded by specific bacteria. Use this expression library by screening apparently just specific gene probe.
DNA repair
DNA repair (DNA repairing) cell DNA damage by the response, this response may resume DNA structure as it is, can re-implementation of its original function, but sometimes are not able to completely eliminate the DNA damage, but cells This tolerance to DNA damage and can continue to survive. Perhaps this has not fully repair the damage and hold down the right conditions will be shown under (such as of cancerous cells, etc.), but if the cells do not have this repair, it is impossible to deal with the frequent occurrence of DNA damage in the incident, survival . Therefore DNA repair research is to explore an important aspect of life, but also with military medicine, oncology, and other closely related. On the different DNA damage, cells can have different repair responses. DNA contains A, C, G and T four bases, under normal circumstances A - T, C - G base pairs combination of a DNA cross-linked files. Interpretation of DNA genes is through these bases in order to convey instructions to the cells, control cells work. Many factors could cause DNA strand breaks, DNA chain in the reorganization to rearrange the base, resulting in the interpretation of the original base sequences and different, send the wrong instructions, resulting in the wrong cell growth and working conditions, variation in the cell, also will have the tumor cells. Tumor cells will absorb a large amount of nutrients or normal human cells grow rapidly, tumor cells than normal cells much larger nucleus than the normal 1-5 times, and more deformed, and so on. At the same time tumor DNA chain in the same situation will be broken, because DNA repair and half with its own reservations about the function of reproduction, DNA ligase can be linked to DNA fragment again in the next rotation of the role of re-forming spiral. And a small section of genetic DNA of tumor cells can generate new characteristics of tumor cells. Now scientists are often referred to cloning, the DNA is the use of this property. So most of the tumor DNA chain reorganization is a change of two or more of a change process, which form the tumor cell replication and propagation, which resulted in tumor expansion, proliferation, transfer and deterioration, and ultimately threaten human health and life.
[DNA replication:
DNA replication is double-stranded DNA prior to cell division in the replication process, the result is copied into a double strand of the double-stranded two different (if the normal process of reproduction), with each double-strand of the double-stranded, like the original . This process is called semi-through replication mechanism to retain the smooth completion. Copy can be divided into the following phases:
Start-up phase: gyrase in local start the double helix structure of DNA molecules a single chain of primers to identify the start bit, in order to solve the section of DNA as a template, according to the 5 'to 3' direction of short-chain RNA synthesis. Forming RNA primer.
DNA fragments generated: provide a primer 3'-OH ends on the basis of DNA polymerase chain of the two catalytic DNA replication process at the same time, because the process can only be copied from the 5'-> 3 'direction synthesis, a chain to continuous synthesis, a separate chain of subparagraph, each of which became a short chain Okazaki fragment (Okazaki fragments).
RNA hydrolysis primer: When a certain length of DNA synthesis, DNA polymerase hydrolysis of RNA primer, Buchen gap.
DNA ligase DNA fragments will phosphate ester bond of linking it to a complete DNA molecule.
Finally new synthetic fragments of DNA gyrase help in the re-formation of spiral.
[Single-strand DNA]
Single-stranded DNA (single-stranded DNA) to the majority of the double helix structure of DNA exist, but the heat or alkaline treatment will be linked into a single state. Single-strand DNA refers to the existence of this state of the DNA. Single strand DNA molecules in the fluid mechanics nature, absorption spectra, base response nature of both double-stranded DNA and different. Certain phage particles containing single-chain ring of DNA, the phage DNA in the cell proliferation when a double-stranded DNA.
Closed-loop [DNA]
Closed-loop DNA (closed circular DNA) did not fracture of the double-stranded circular DNA, which is also known as super-helical DNA. Due to the double-stranded helical structure of their closure, with the result that the entire DNA molecule further spin-formed three-tier structure. If another one or two different parts of the chain have a fracture, it will become a Rotary song open-loop DNA molecule. Extracted from the cells in the plasmid or viral DNA contains the closed-loop and open-loop that two kinds of molecules. According to the two pigment can be combined with the ability of different, and both will be separated from.
DNA [link]
DNA link (Linker DNA): nuclear body, in addition to 146 bp DNA, the core of all DNA.
[Template DNA]
Template DNA can be single-chain molecule, it can also be a double-stranded molecule, it could be linear elements, it can also be a cyclic molecules (molecular ratio ring linear amplification effect of a lesser extent). On the template DNA, PCR impact The main factor is the number of templates and purity.
[Complementary DNA]
Complementary DNA (cDNA, complementary DNA) gene of a double-stranded DNA molecule with a single chain as a template, the transcription produce its sequence complementary messenger RNA molecules, and then the role of reverse transcriptase, to mRNA molecules as templates, and a Synthesis mRNA sequence complementary single strand DNA, and finally a single-stranded DNA as a template synthesis another one with the complementary single strand DNA, the two complementary single strand DNA molecules to form a double-stranded cDNA molecule. Therefore, the double-stranded cDNA sequence elements with the mRNA transcription of the gene is the same. therefore a cDNA molecule on behalf of a gene. cDNA but still different from the genes, because a gene mRNA transcription, coding some of the intron sequence that was deleted, retained only the coding sequence, that is, Exon. cDNA sequence than it should be much shorter sequence, because cDNA gene are not included in the non-coding sequences - intron.
[DNA restriction fragment length polymorphism analysis:
In the human genome, an average of about 200 pairs a base mutation can occur (known as the neutral mutations), neutral mutations lead to inter-individual differences in nucleotide sequence, known as DNA polymorphism. Many polymorphisms in DNA restriction enzyme recognition site, the enzyme DNA fragment length will be a different fragment, known as restriction fragment length polymorphism (RFLP). RFLR way by Mendelian genetics, in a particular family, and if a disease-specific gene fragment polymorphism closely linked polymorphic fragments that can be used as a kind of "genetic markers" to family members or judgement whether fetal genes that cause carriers. A hemophilia, cystic fibrosis and phenylketonuria, and other lesions can be diagnosed using this method.
[ "Junk DNA"]
[ "Junk DNA"]
Yeast and worms like how simple biological evolution for birds and mammals such complex biological? A view of the extensive genome comparative study shows that the answer may be hidden in the garbage of deoxyribonucleic acid (DNA). American scientists found that the more complex biological, carrying the more junk DNA, and it is not coding these "useless" DNA help higher organisms evolved a complex organism.
Since the first eukaryotes - ranging from yeast to humans by the biological cell - the genome has been deciphered, scientists have wanted to know why the majority of DNA and has not formed a useful genes. From the chromosome mutation protection to the structure of support for this so-called junk DNA may explain many of the species. But last year from the human, mouse and rat are on the complete consensus on the junk DNA research, it showed that in this region may contain an important adjustment mechanism, which can control the basis of biochemical reactions and development process This will help the biological evolution of a more complex organism. And simple eukaryotes compared to more complex biological mutations in the gene will not doubt the fact that this has greatly strengthened found.
To this deeper understanding of the problem, by the United States at the University of California, Santa Cruz (UCSC) biologist David Haussler of the leadership of a research group, the five kinds of vertebrate animals - people, mice, rats , chicken and blowfish - junk DNA sequence and four kinds of insects, worms, and two of the seven kinds of junk DNA sequence of yeast were compared. Comparative results from the study received a shocking pattern: The more complex biological, junk DNA seems to be more important.
Among these is the possibility of implicit, if different types of biological have the same DNA, then the DNA must be used to solve some key problems. Yeast and vertebrates share a certain amount of DNA, after all, they all need to make proteins, but only 15% of the total DNA and gene irrelevant. Research Group in the July 14 "Genome Research" magazine online report that they will be more complex yeast and worms were compared, the latter is a multi-cell biology, found that 40% of the total DNA was not coding . Subsequently, the researchers will invertebrates and insects were compared, these organisms more complex than worms, the results showed that more than 66% of the total DNA contains no coding DNA.
Participate in the study of the work of the UCSC biologist Adam Siepel pointed out that the worm's findings needs to be cautiously treated, it is only because of these scientists of the two genomes were analyzed. Nevertheless, Siepel believes that the findings strongly support such a theory, that is, invertebrates and insects in the biological complexity of the increase is mainly due to the precise gene regulation patterns.
Yeast and worms like how simple biological evolution for birds and mammals such complex biological? A view of the extensive genome comparative study shows that the answer may be hidden in the garbage of deoxyribonucleic acid (DNA). American scientists found that the more complex biological, carrying the more junk DNA, and it is not coding these "useless" DNA help higher organisms evolved a complex organism.
Since the first eukaryotes - ranging from yeast to humans by the biological cell - the genome has been deciphered, scientists have wanted to know why the majority of DNA and has not formed a useful genes. From the chromosome mutation protection to the structure of support for this so-called junk DNA may explain many of the species. But last year from the human, mouse and rat are on the complete consensus on the junk DNA research, it showed that in this region may contain an important adjustment mechanism, which can control the basis of biochemical reactions and development process This will help the biological evolution of a more complex organism. And simple eukaryotes compared to more complex biological mutations in the gene will not doubt the fact that this has greatly strengthened found.
To this deeper understanding of the problem, by the United States at the University of California, Santa Cruz (UCSC) biologist David Haussler of the leadership of a research group, the five kinds of vertebrate animals - people, mice, rats , chicken and blowfish - junk DNA sequence and four kinds of insects, worms, and two of the seven kinds of junk DNA sequence of yeast were compared. Comparative results from the study received a shocking pattern: The more complex biological, junk DNA seems to be more important.
Among these is the possibility of implicit, if different types of biological have the same DNA, then the DNA must be used to solve some key problems. Yeast and vertebrates share a certain amount of DNA, after all, they all need to make proteins, but only 15% of the total DNA and gene irrelevant. Research Group in the July 14 "Genome Research" magazine online report that they will be more complex yeast and worms were compared, the latter is a multi-cell biology, found that 40% of the total DNA was not coding . Subsequently, the researchers will invertebrates and insects were compared, these organisms more complex than worms, the results showed that more than 66% of the total DNA contains no coding DNA.
Participate in the study of the work of the UCSC biologist Adam Siepel pointed out that the worm's findings needs to be cautiously treated, it is only because of these scientists of the two genomes were analyzed. Nevertheless, Siepel believes that the findings strongly support such a theory, that is, invertebrates and insects in the biological complexity of the increase is mainly due to the precise gene regulation patterns.
[Human Genome Project:
[Human Genome Project:
The Human Genome Project (human genome project, HGP) by the United States in 1985, scientists first proposed in 1990 formally activated. United States, the United Kingdom, the Republic of France, the Federal Republic of Germany, Japan and Chinese scientists has been involved in the total value of 3 billion US dollars of the Human Genome Project. The scheme aims to more than 3 billion base pairs that constitute the precise sequencing of the human genome, and found that all human genes and make clear its position on the chromosome, all in deciphering the human genetic information. Manhattan and the Apollo moon-landing plan and plans and called the three major scientific project.
June 26, 2000, to participate in the human genome project in the United States, the United Kingdom, the Republic of France, the Federal Republic of Germany, Japan and China together scientists of the six countries that the draft human genome mapping has been completed. Map calls for completion of the final sequence can be used in cloning often faithfully represent chromosome genome structure, sequence error rate less than 1 in 10,000. 95% chromatin regions are often sequenced, each less than 150 kb Gap. Completed plans will be completed in 2003, two years earlier than expected.
United States and British scientists May 18, 2006 in the United Kingdom "Nature" magazine published on the Internet version of the last of the human chromosomes - 1 gene of chromosome sequencing.
In all 22 pairs of human chromosomes often, the gene on chromosome 1 contains the largest number to 3141, is twice the average level, a total of more than 223 million base pairs right, the greatest difficulty deciphering. A 150 British and American scientists took a team of 10, was completed on the 1st of chromosome sequencing work.
Scientists announced that more than once the completion of the human genome project, but not all were launched this, this time fixing the "book of life" more precise, covering the human genome 99.99%. Interpretation of the human genetic code, "a book of life," declared completed, lasted 16 human genome project finished writing the final chapter.
History of the development of DNA
DNA is the 1944 Avery discovered by the Americans. Professor Crick in 1953 to map out the DNA double helix structure. 1985 Alec Jeffreys of Leicester University, and professor of human invention of the use of DNA to identify solutions. DNA since start of 1988 in the administration of justice. July 29, 1994, French law provides for the use of genetic markers conditions.
According to scientific analysis, each individual has 400 trillion cells (skin, muscle, nerve, etc.), in addition to human red blood cells, all cells have 46 chromosomes from a composition of the nucleus DNA from chromosome itself is a silk chromosome, which Chromosome silk in all cells is the same. DNA from known as A (adenine), T (thymine), G (guanine) and C (cytosine) nucleic acid composition, it is they constitute our human genes. According to DNA it can be concluded between the two generations of people who have genetic relationship as a child always from the fathers and mothers who receive half of the genetic material. Scientists also study the DNA target on identifying genes causing people to fall ill origin, in order to better understand the future, treatment and prevention of hazards to human health of diseases.
DNA credibility? Chromosome whether two people will be similar? According to scientific experiments, and such a possibility only 1/10000000. However, in the course of all errors will be possible, mainly in the extraction and testing of specimens, specimens may also be another person's DNA contamination. In order to ensure the reliability of DNA must be extracted samples and laboratory analysis of strict checks. Now, as a result of the genome sequence of the new development plan and equipment, not only can avoid possible mistakes, but also greatly accelerate the speed of the DNA test.
The Human Genome Project (human genome project, HGP) by the United States in 1985, scientists first proposed in 1990 formally activated. United States, the United Kingdom, the Republic of France, the Federal Republic of Germany, Japan and Chinese scientists has been involved in the total value of 3 billion US dollars of the Human Genome Project. The scheme aims to more than 3 billion base pairs that constitute the precise sequencing of the human genome, and found that all human genes and make clear its position on the chromosome, all in deciphering the human genetic information. Manhattan and the Apollo moon-landing plan and plans and called the three major scientific project.
June 26, 2000, to participate in the human genome project in the United States, the United Kingdom, the Republic of France, the Federal Republic of Germany, Japan and China together scientists of the six countries that the draft human genome mapping has been completed. Map calls for completion of the final sequence can be used in cloning often faithfully represent chromosome genome structure, sequence error rate less than 1 in 10,000. 95% chromatin regions are often sequenced, each less than 150 kb Gap. Completed plans will be completed in 2003, two years earlier than expected.
United States and British scientists May 18, 2006 in the United Kingdom "Nature" magazine published on the Internet version of the last of the human chromosomes - 1 gene of chromosome sequencing.
In all 22 pairs of human chromosomes often, the gene on chromosome 1 contains the largest number to 3141, is twice the average level, a total of more than 223 million base pairs right, the greatest difficulty deciphering. A 150 British and American scientists took a team of 10, was completed on the 1st of chromosome sequencing work.
Scientists announced that more than once the completion of the human genome project, but not all were launched this, this time fixing the "book of life" more precise, covering the human genome 99.99%. Interpretation of the human genetic code, "a book of life," declared completed, lasted 16 human genome project finished writing the final chapter.
History of the development of DNA
DNA is the 1944 Avery discovered by the Americans. Professor Crick in 1953 to map out the DNA double helix structure. 1985 Alec Jeffreys of Leicester University, and professor of human invention of the use of DNA to identify solutions. DNA since start of 1988 in the administration of justice. July 29, 1994, French law provides for the use of genetic markers conditions.
According to scientific analysis, each individual has 400 trillion cells (skin, muscle, nerve, etc.), in addition to human red blood cells, all cells have 46 chromosomes from a composition of the nucleus DNA from chromosome itself is a silk chromosome, which Chromosome silk in all cells is the same. DNA from known as A (adenine), T (thymine), G (guanine) and C (cytosine) nucleic acid composition, it is they constitute our human genes. According to DNA it can be concluded between the two generations of people who have genetic relationship as a child always from the fathers and mothers who receive half of the genetic material. Scientists also study the DNA target on identifying genes causing people to fall ill origin, in order to better understand the future, treatment and prevention of hazards to human health of diseases.
DNA credibility? Chromosome whether two people will be similar? According to scientific experiments, and such a possibility only 1/10000000. However, in the course of all errors will be possible, mainly in the extraction and testing of specimens, specimens may also be another person's DNA contamination. In order to ensure the reliability of DNA must be extracted samples and laboratory analysis of strict checks. Now, as a result of the genome sequence of the new development plan and equipment, not only can avoid possible mistakes, but also greatly accelerate the speed of the DNA test.
[DNA] ultracentrifugation
[DNA] ultracentrifugation
Modern plasmid DNA isolation and purification by separation from the E. coli represented, in view of the overall situation bacilli (E.coli) in the molecular biology of the important position in the separation and purification from E.coli DNAa quality control In recent years in the ultra-centrifuge technology is an important topic. Fast and plasmid DNA isolation and purification equipment and the ultra-centrifugation (speed centrifuges, the old and ancillary equipment) has put a higher demand.
E.coli is a typical prokaryotic cell biology, because of the lack of prokaryotic cells with its nuclear cells from the kind of film units composed of a variety of functional components can be separated for the specificity of regional and local independent of the endometriosis, therefore not covered by its nuclear cell of the cell (nucleus, endoplasmic reticulum, golgi apparatus, the line of Rafah, lysosomes, etc.). SEM micrographs showed that E.coli can be two different regions within the cytoplasm and the nucleus and cytoplasm January 1, in their thin layer around the outside of the cell membrane and very thick cell wall and cell wall in the end some external attachment of the free flagella. Plasmid DNA in the nucleus to filamentous exist, such filaments bar in a variety of circumstances is very long circular DNA fragments some of the folding up of poly body.
Microstructure against E.coli question, in ultra-centrifugal separation and purification of plasmid DNA sequence pretreatment before: E.coli → → with lysozyme to the cell wall using surfactants such as SDS, Trit X-100 membrane → EE, such as acetic acid used pot to DNA, RNA and protein precipitation majority (more than 90%).
Sediments can be joined in TE buffer (10-m-MTris HCL lmMEDTA, pH8.0) to live on protein molecular sieve to RNA; also can be used to ultracentrifugation protein Habitat to RNA to DNA-level DNA fragments or .
[Ultracentrifugation Plasmid DNA Isolation Method]
The traditional separation methods: a few years ago, due to equipment constraints, plasmid DNA from the general balance by CsCl density centrifugation, since the formation of gradient. 10 ~ 12 ml single-tube capacity as an example, using the old left-separation, 36.000 rpm × 60-hour separation with the old angle-45, OOOrpm × 36 hours, including acceleration and deceleration, the former spent 130 million to the Department of Driver Life, which spent 100 million to the drive to life, and this life was speeding centrifuge total of 100 ~ to 20 billion, no doubt each with excessive costs, coupled with CsCl consumption, high cost and other factors so that such separation and purification work a very expensive experiment.
[Plasmid DNA ultracentrifugation from the latest developments:
(1) speed of the old vertical centrifugal separation (titanium alloy or carbon fibre): From 1975 to the old vertical tube WHO, in recent years the major development of the centrifuge manufacturer of the old vertical, single-tube capacity 0.2 Oml to 4 ml, the maximum speed from 50,000 rpm to 120,000 rpm, RCFmax up to 700, OOOXg 1990s and the development of new models has been able to make the old vertical tube plasmid DNA test done centrifugal separation easier.
(2) near-vertical centrifugal separation of the old: In order to remove the old vertical tube used for plasmid DNA in the wall of the centrifuge formation of RNA precipitation has been formed on the DNA zone pollution, but also to improve the old-general diagonal (dip 25 • - 35 •) from the settlement because of a longer and therefore a longer time separated the shortcomings of the past few years the development of a wide range of near-vertical pipe the old (Near VerticalTube Rot, as the old NVT or Neo Angle Rotor, small angle at the old, or NT). their profile centrifuge tube and centrifuge central axis drive in the angle between the axis of 7.5 • - 10 • between speed from 120 to 65,000 rpm, OOOrpm, RCFmax up to 646000 × g single-tube capacity from 2 ml to 13.5 ml. NVT (or NT) is the development of the old plasmid DNA isolation and for the design, of course, also applies to mitochondrial DNA, chromosomal DNA, RNA and serum lipoprotein • Isolation and purification.
(3) discontinuous gradient separation ladder: DNA Isolation and Purification of the school is the traditional method used since the formation of CsCl density gradient centrifugation balance, at the beginning of the centrifuge tube CsCl density uniform, uniform distribution of these samples.
Modern plasmid DNA isolation and purification by separation from the E. coli represented, in view of the overall situation bacilli (E.coli) in the molecular biology of the important position in the separation and purification from E.coli DNA
E.coli is a typical prokaryotic cell biology, because of the lack of prokaryotic cells with its nuclear cells from the kind of film units composed of a variety of functional components can be separated for the specificity of regional and local independent of the endometriosis, therefore not covered by its nuclear cell of the cell (nucleus, endoplasmic reticulum, golgi apparatus, the line of Rafah, lysosomes, etc.). SEM micrographs showed that E.coli can be two different regions within the cytoplasm and the nucleus and cytoplasm January 1, in their thin layer around the outside of the cell membrane and very thick cell wall and cell wall in the end some external attachment of the free flagella. Plasmid DNA in the nucleus to filamentous exist, such filaments bar in a variety of circumstances is very long circular DNA fragments some of the folding up of poly body.
Microstructure against E.coli question, in ultra-centrifugal separation and purification of plasmid DNA sequence pretreatment before: E.coli → → with lysozyme to the cell wall using surfactants such as SDS, Trit X-100 membrane → EE, such as acetic acid used pot to DNA, RNA and protein precipitation majority (more than 90%).
Sediments can be joined in TE buffer (10-m-MTris HCL lmMEDTA, pH8.0) to live on protein molecular sieve to RNA; also can be used to ultracentrifugation protein Habitat to RNA to DNA-level DNA fragments or .
[Ultracentrifugation Plasmid DNA Isolation Method]
The traditional separation methods: a few years ago, due to equipment constraints, plasmid DNA from the general balance by CsCl density centrifugation, since the formation of gradient. 10 ~ 12 ml single-tube capacity as an example, using the old left-separation, 36.000 rpm × 60-hour separation with the old angle-45, OOOrpm × 36 hours, including acceleration and deceleration, the former spent 130 million to the Department of Driver Life, which spent 100 million to the drive to life, and this life was speeding centrifuge total of 100 ~ to 20 billion, no doubt each with excessive costs, coupled with CsCl consumption, high cost and other factors so that such separation and purification work a very expensive experiment.
[Plasmid DNA ultracentrifugation from the latest developments:
(1) speed of the old vertical centrifugal separation (titanium alloy or carbon fibre): From 1975 to the old vertical tube WHO, in recent years the major development of the centrifuge manufacturer of the old vertical, single-tube capacity 0.2 Oml to 4 ml, the maximum speed from 50,000 rpm to 120,000 rpm, RCFmax up to 700, OOOXg 1990s and the development of new models has been able to make the old vertical tube plasmid DNA test done centrifugal separation easier.
(2) near-vertical centrifugal separation of the old: In order to remove the old vertical tube used for plasmid DNA in the wall of the centrifuge formation of RNA precipitation has been formed on the DNA zone pollution, but also to improve the old-general diagonal (dip 25 • - 35 •) from the settlement because of a longer and therefore a longer time separated the shortcomings of the past few years the development of a wide range of near-vertical pipe the old (Near VerticalTube Rot, as the old NVT or Neo Angle Rotor, small angle at the old, or NT). their profile centrifuge tube and centrifuge central axis drive in the angle between the axis of 7.5 • - 10 • between speed from 120 to 65,000 rpm, OOOrpm, RCFmax up to 646000 × g single-tube capacity from 2 ml to 13.5 ml. NVT (or NT) is the development of the old plasmid DNA isolation and for the design, of course, also applies to mitochondrial DNA, chromosomal DNA, RNA and serum lipoprotein • Isolation and purification.
(3) discontinuous gradient separation ladder: DNA Isolation and Purification of the school is the traditional method used since the formation of CsCl density gradient centrifugation balance, at the beginning of the centrifuge tube CsCl density uniform, uniform distribution of these samples.
[DNA paternity testing]
[DNA paternity testing]
At present, identification of the parent-child relationship was most of the DNA typing identification. Person's blood, hair, saliva, buccal cell, and so can be used for paternity testing, is very convenient.
A person has 23 pairs (46) chromosome, the same position on the same chromosome a gene known as alleles, a general from the father and one from the mother. If DNA testing to a site alleles, as a mother, father and another should be the same, otherwise there is questionable.
The use of DNA for paternity testing, as long as a dozen to a few dozen sites for DNA testing, if all the same, you can define the parent-child relationship, if there are more than three different sites, the parent-child relationship can be ruled out, 12-bit the difference, they should consider the possibility of gene mutations, and some of the sites to identify. DNA paternity testing, and negate the accuracy of the parent-child relationship almost 100 percent, certainly the accuracy of the parent-child relationship can be achieved 99.99%.
DNA paternity testing test FAQ
What is a DNA paternity test test?
DNA (deoxyribonucleic acid) is a physical body cells atomic material. Each atom has 46 chromosomes, while men's sperm and the woman's egg cell, and each has 23 chromosomes, the sperm and eggs of the time. This on chromosome 46 atoms to create a life, therefore, each inherited from the father half of the molecular substance, while the other half received from the mother.
DNA paternity testing test with the traditional blood tests are quite different. It can be conducted on a sample of different tests, including blood, gills cavity cells, tissue samples and semen samples. Because blood type, such as Type A, Type B, Type O or Type RH, in the population is relatively common, for the resolution of each individual, DNA paternity testing is not an effective test. Apart from the real twins, each person's DNA is unique. Because it is so unique, just like fingerprints, for paternity testing, DNA is the most effective method. Our results than is normally requested by the court also accurate from 10 to 100 times.
At present, identification of the parent-child relationship was most of the DNA typing identification. Person's blood, hair, saliva, buccal cell, and so can be used for paternity testing, is very convenient.
A person has 23 pairs (46) chromosome, the same position on the same chromosome a gene known as alleles, a general from the father and one from the mother. If DNA testing to a site alleles, as a mother, father and another should be the same, otherwise there is questionable.
The use of DNA for paternity testing, as long as a dozen to a few dozen sites for DNA testing, if all the same, you can define the parent-child relationship, if there are more than three different sites, the parent-child relationship can be ruled out, 12-bit the difference, they should consider the possibility of gene mutations, and some of the sites to identify. DNA paternity testing, and negate the accuracy of the parent-child relationship almost 100 percent, certainly the accuracy of the parent-child relationship can be achieved 99.99%.
DNA paternity testing test FAQ
What is a DNA paternity test test?
DNA (deoxyribonucleic acid) is a physical body cells atomic material. Each atom has 46 chromosomes, while men's sperm and the woman's egg cell, and each has 23 chromosomes, the sperm and eggs of the time. This on chromosome 46 atoms to create a life, therefore, each inherited from the father half of the molecular substance, while the other half received from the mother.
DNA paternity testing test with the traditional blood tests are quite different. It can be conducted on a sample of different tests, including blood, gills cavity cells, tissue samples and semen samples. Because blood type, such as Type A, Type B, Type O or Type RH, in the population is relatively common, for the resolution of each individual, DNA paternity testing is not an effective test. Apart from the real twins, each person's DNA is unique. Because it is so unique, just like fingerprints, for paternity testing, DNA is the most effective method. Our results than is normally requested by the court also accurate from 10 to 100 times.
The development of recombinant DNA technology
[The development of recombinant DNA technology --
In the 1950s, the double helix structure of DNA was explained, has opened a new chapter in the life sciences, opening up a new era of science and technology. Subsequently, the molecular mechanism of genetic - DNA replication, genetic code, genetic information transfer rules at the centre, as the basic unit of genetic engineering and cell gene blueprint for the regulation and control of gene expression and have been recognized. So far, it has been fully aware of all the biological control is the fate of the things it contains DNA and the genetic, biological evolution and the different life course, it is because the operation of DNA and gene locus different.
Aware of the important role of DNA and values, life scientists can begin thinking in certain closely related to the interests and the human aspects of the natural genetic break the iron rule, the prevalence of gene改邪归正to cure purpose of the different sources of gene fragments "pharming," in order to produce new varieties and new quality…… Thus, the temptation of a full scientific fantasy miraculously become a reality. This is the 20th century occurred in the early 1970s things.
Achieve this scientific miracle means of science and technology is recombinant DNA technology. 1972, the United States scientist Paul Berg first successful restructuring of the world's first batch of DNA molecule, marking recombinant DNA technology - genetic engineering as the basis of modern bio-engineering, modern biotechnology and the life sciences, the foundation and core of .
Recombinant DNA technology is the adoption of the specific content of artificial means will be different sources of a specific DNA fragment of the gene reorganization in order to achieve change of a specific gene type and the purpose of the gene product of a high-science and technology.
By the late 1970s, the emergence of projects and the achievement of recombinant DNA and post-processing projects are of the nature, genetic engineering or genetic engineering as a synonym for recombinant DNA technology is widely used. Now, genetic engineering also includes the transformation of genomic DNA sequence analysis, molecular evolution analysis, molecular immunology, gene cloning, gene therapy and gene diagnosis, and so forth. It can be said that the creation of recombinant DNA technology nearly 30 years has obtained great achievements of the people into a fantastic incredible scientific world, human life was a mystery and open for preventing and curing diseases, "Box" gold key.
At present, recombinant DNA technology has already been achieved in many ways. To the end of the 20th century, the largest recombinant DNA technology applications in medicine, including active peptides, proteins and vaccine production, disease pathogenesis, diagnosis and treatment, the new gene separation and purification, and environmental monitoring.
Many active peptides and proteins have the treatment and prevention of disease, and they are from the corresponding gene in the. However, because the tissue production is very low, so it is difficult using conventional methods sufficient quantity for clinical application.
A breakthrough in genetic engineering, this limitation can be mass production of such peptides and proteins, have been successfully produced and schizophrenia treatment of diabetic insulin, the blood and certain solid tumors therapeutic antivirals -- Interferon treatment Zhouruzheng of human growth hormone, treatment Acromegaly and acute pancreatitis, such as growth hormone releasing factor inhibiting more than 100 kinds of products.
Genetic engineering can also be relevant antigens into the DNA of living organisms, such microorganisms in by the host immune stress can be generated in vivo growth of live attenuated vaccines, a large dose of antigen stimulation, and lasted for a long time, and other benefits. Currently being developed genetically engineered vaccine alone dozens, in terms of dealing with leprosy bacteria have against bacteria, pertussis bacteria, Neisseria gonorrhoeae, such as the meningococcal vaccine to combat the virus have against hepatitis A, hepatitis B , cytomegalovirus, herpes simplex, influenza, such as human immunodeficiency virus vaccine……. Hepatitis B virus carriers in China and as many as 412 million hepatitis B patients, the situation is even encouraged Chinese scientists successfully developed its own hepatitis B vaccine, made tremendous social and economic benefits.
Antibodies are the body's immune system disease prevention one of the main weapons in the 20th century, the 1970s creation of monoclonal antibody technology in the aspects of preventing resistance played an important role, but because human monoclonal antibody difficult to obtain, making single - Anti-clinical application is limited. To address the problem, in recent years scientists used recombinant DNA technology has been a human antibody, the antibody can guarantee it with the antigen-binding specificity and affinity can ensure that the normal functioning of play. At present, there are a variety of antibodies that a clinical trial, such as the anti-HER-2 monoclonal antibody treatment of human breast cancer has entered the stage Ⅲ test, anti-IGE human monoclonal antibody treatment of asthma has entered Phase Ⅱ.
Antibiotics in the treatment of diseases has played an important role, along with the increase in the number of antibiotics, using traditional methods of discovering new antibiotics likely getting lower and lower. In order to obtain more new antibiotics, using recombinant DNA technology has become an important means of one. Currently people have been dozens of genetic engineering "hybrid" of antibiotics for clinical application has opened up a new therapeutic approach.
It is worth noting that the above genetically engineered peptides, proteins, vaccines, antibiotics and other drugs not only in the effective control disease control, and to avoid side effects also often superior to the traditional methods of production of similar drugs, making it more favored by the people .
Human diseases are directly or indirectly associated with the gene, the gene at the level of diagnosis and treatment of disease, the diagnosis can achieve the accuracy and primitive, and the diagnosis and treatment can achieve strong specificity, high sensitivity, simple Fast purposes. At the level of genes in the diagnosis and treatment of professional called genetic diagnosis and gene therapy. At present genetic diagnosis as a fourth-generation clinical diagnosis technology has been widely used for genetic diseases, cancer, cardiovascular and cerebrovascular diseases, viruses, bacteria and parasitic diseases such as the diagnosis of occupational diseases, and the goal of gene therapy is through recombinant DNA technology to create a specific recombinant gene function to compensate for the loss of the gene function, or a function to facilitate the increase of abnormal cells corrected or eliminated.
In theory, gene therapy to tackle the cured without any side effects of treatment. However, despite the international community so far has been more than 100 gene therapy programme is in a clinical trial phase, but the gene therapy in theory and in a number of technical problems still to this treatment from the large-scale application there is a long distance. Determine whether the gene causes or genetic diagnosis, gene therapy, study the mechanism of disease, the key prerequisite for it is necessary to understand the specific disease-related genes. Along with the "Human Genome Project" is approaching completion, the scientists of all human genes will be comprehensive understanding of this technology for the use of recombinant human health made forced to create conditions for the cause.
However, although the human gene technology to display its wonderful "magician" like charm, but there are also a large number of scientists on the development of this technology to human ethics and the evolution of the ecological impact of the laws of nature expressed great concern. Theoretically speaking, the development of this technology is a limit to human life with the creation of any form or have never biological capacity. People can imagine how this will be the outcome?
In the 1950s, the double helix structure of DNA was explained, has opened a new chapter in the life sciences, opening up a new era of science and technology. Subsequently, the molecular mechanism of genetic - DNA replication, genetic code, genetic information transfer rules at the centre, as the basic unit of genetic engineering and cell gene blueprint for the regulation and control of gene expression and have been recognized. So far, it has been fully aware of all the biological control is the fate of the things it contains DNA and the genetic, biological evolution and the different life course, it is because the operation of DNA and gene locus different.
Aware of the important role of DNA and values, life scientists can begin thinking in certain closely related to the interests and the human aspects of the natural genetic break the iron rule, the prevalence of gene改邪归正to cure purpose of the different sources of gene fragments "pharming," in order to produce new varieties and new quality…… Thus, the temptation of a full scientific fantasy miraculously become a reality. This is the 20th century occurred in the early 1970s things.
Achieve this scientific miracle means of science and technology is recombinant DNA technology. 1972, the United States scientist Paul Berg first successful restructuring of the world's first batch of DNA molecule, marking recombinant DNA technology - genetic engineering as the basis of modern bio-engineering, modern biotechnology and the life sciences, the foundation and core of .
Recombinant DNA technology is the adoption of the specific content of artificial means will be different sources of a specific DNA fragment of the gene reorganization in order to achieve change of a specific gene type and the purpose of the gene product of a high-science and technology.
By the late 1970s, the emergence of projects and the achievement of recombinant DNA and post-processing projects are of the nature, genetic engineering or genetic engineering as a synonym for recombinant DNA technology is widely used. Now, genetic engineering also includes the transformation of genomic DNA sequence analysis, molecular evolution analysis, molecular immunology, gene cloning, gene therapy and gene diagnosis, and so forth. It can be said that the creation of recombinant DNA technology nearly 30 years has obtained great achievements of the people into a fantastic incredible scientific world, human life was a mystery and open for preventing and curing diseases, "Box" gold key.
At present, recombinant DNA technology has already been achieved in many ways. To the end of the 20th century, the largest recombinant DNA technology applications in medicine, including active peptides, proteins and vaccine production, disease pathogenesis, diagnosis and treatment, the new gene separation and purification, and environmental monitoring.
Many active peptides and proteins have the treatment and prevention of disease, and they are from the corresponding gene in the. However, because the tissue production is very low, so it is difficult using conventional methods sufficient quantity for clinical application.
A breakthrough in genetic engineering, this limitation can be mass production of such peptides and proteins, have been successfully produced and schizophrenia treatment of diabetic insulin, the blood and certain solid tumors therapeutic antivirals -- Interferon treatment Zhouruzheng of human growth hormone, treatment Acromegaly and acute pancreatitis, such as growth hormone releasing factor inhibiting more than 100 kinds of products.
Genetic engineering can also be relevant antigens into the DNA of living organisms, such microorganisms in by the host immune stress can be generated in vivo growth of live attenuated vaccines, a large dose of antigen stimulation, and lasted for a long time, and other benefits. Currently being developed genetically engineered vaccine alone dozens, in terms of dealing with leprosy bacteria have against bacteria, pertussis bacteria, Neisseria gonorrhoeae, such as the meningococcal vaccine to combat the virus have against hepatitis A, hepatitis B , cytomegalovirus, herpes simplex, influenza, such as human immunodeficiency virus vaccine……. Hepatitis B virus carriers in China and as many as 412 million hepatitis B patients, the situation is even encouraged Chinese scientists successfully developed its own hepatitis B vaccine, made tremendous social and economic benefits.
Antibodies are the body's immune system disease prevention one of the main weapons in the 20th century, the 1970s creation of monoclonal antibody technology in the aspects of preventing resistance played an important role, but because human monoclonal antibody difficult to obtain, making single - Anti-clinical application is limited. To address the problem, in recent years scientists used recombinant DNA technology has been a human antibody, the antibody can guarantee it with the antigen-binding specificity and affinity can ensure that the normal functioning of play. At present, there are a variety of antibodies that a clinical trial, such as the anti-HER-2 monoclonal antibody treatment of human breast cancer has entered the stage Ⅲ test, anti-IGE human monoclonal antibody treatment of asthma has entered Phase Ⅱ.
Antibiotics in the treatment of diseases has played an important role, along with the increase in the number of antibiotics, using traditional methods of discovering new antibiotics likely getting lower and lower. In order to obtain more new antibiotics, using recombinant DNA technology has become an important means of one. Currently people have been dozens of genetic engineering "hybrid" of antibiotics for clinical application has opened up a new therapeutic approach.
It is worth noting that the above genetically engineered peptides, proteins, vaccines, antibiotics and other drugs not only in the effective control disease control, and to avoid side effects also often superior to the traditional methods of production of similar drugs, making it more favored by the people .
Human diseases are directly or indirectly associated with the gene, the gene at the level of diagnosis and treatment of disease, the diagnosis can achieve the accuracy and primitive, and the diagnosis and treatment can achieve strong specificity, high sensitivity, simple Fast purposes. At the level of genes in the diagnosis and treatment of professional called genetic diagnosis and gene therapy. At present genetic diagnosis as a fourth-generation clinical diagnosis technology has been widely used for genetic diseases, cancer, cardiovascular and cerebrovascular diseases, viruses, bacteria and parasitic diseases such as the diagnosis of occupational diseases, and the goal of gene therapy is through recombinant DNA technology to create a specific recombinant gene function to compensate for the loss of the gene function, or a function to facilitate the increase of abnormal cells corrected or eliminated.
In theory, gene therapy to tackle the cured without any side effects of treatment. However, despite the international community so far has been more than 100 gene therapy programme is in a clinical trial phase, but the gene therapy in theory and in a number of technical problems still to this treatment from the large-scale application there is a long distance. Determine whether the gene causes or genetic diagnosis, gene therapy, study the mechanism of disease, the key prerequisite for it is necessary to understand the specific disease-related genes. Along with the "Human Genome Project" is approaching completion, the scientists of all human genes will be comprehensive understanding of this technology for the use of recombinant human health made forced to create conditions for the cause.
However, although the human gene technology to display its wonderful "magician" like charm, but there are also a large number of scientists on the development of this technology to human ethics and the evolution of the ecological impact of the laws of nature expressed great concern. Theoretically speaking, the development of this technology is a limit to human life with the creation of any form or have never biological capacity. People can imagine how this will be the outcome?
[The discovery of DNA]
[The discovery of DNA]
Since the Mendelian genetic law was rediscovered after, it has raised a question: genetic factor is not a material entity? In order to address the question of what genes are, people are starting to nucleic acid and protein research.
As early as 1868, people had discovered the DNA. German chemist in the laboratory Hepei Le, a graduate Mingjiaomixieer Swiss (1844 - 1895), his laboratory near a hospital threw a bandage with a flu Nongxue interested, because he knows that in order to defend those Nongxie human health and disease " 'operations," and died in the WBC and the human cells were killed "remains." So he carefully bandage on the Nongxue collection, and using pepsin to break it down, found the bodies of most of the cell decomposition, but the nuclear non-functional. He further analysis of nucleus material found in the nucleus containing a phosphorus and nitrogen-rich material. Hepei Le experiments with yeast, that the nucleus of Michel substances found to be correct. So he would give such nuclei isolated from the material named "radionuclide", but found it was acidic and therefore diverted called "nucleic acids." Since then people have carried out a series of effective nucleic acid research.
In the early 20th century, Germany Kesaier (1853 - 1927) and two of his students Jones (1865 - 1935) and in the text (1869 - 1940) study, made clear the basic chemical structure of DNA, that it Nucleotide is composed of many macromolecules. By the nucleotide bases, consisting of phosphate and ribose. There are four kinds of bases (adeno-Piao Yin, the birds purine, thymine and cytosine), there are two ribose (ribosomes, deoxyribose), the nucleic acid into ribonucleic acid (RNA) and deoxyribonucleic acid ( DNA).
In a hurry to the text of his research results, erroneously think that the four kinds of bases in DNA is in the amount equal to nucleic acids derived from the basic structure of four nucleotide bases with different connections into the four nucleosides Acid as a basis for a nucleic acid polymer, proposed a "four nucleotide hypothesis." This hypothesis wrong, the understanding of the complexity of DNA structure considerable impediment, to a certain extent, affected the people's understanding of the function of nucleic acids. It was felt that although the nucleic acid present in the structure of the important - the nucleus, but its structure is too simple, it is difficult to envisage it in the genetic processes in what role.
Protein than the discovery of DNA as early as 30, have developed rapidly. The beginning of the 20th century, composed of 20 kinds of amino acid protein of 12 species have been found, in 1940, all were found.
1902, a German chemist for Xieerchi between amino acid peptide chain connected to the formation of protein theory, in 1917 he was synthesized from 15 glycine and three leucine composed of 18 long-chain peptide . Therefore, the idea of some scientists is possible that the genetic proteins play a major role. If the nucleic acid involved in genetic role, but also must be linked with the protein in the NP role. Therefore, when biological protein is generally inclined to think that the carrier of genetic information.
1928, the United States scientists Griffith (1877 - 1941) in an Clostridium perfringens, and a toxic-free capsule, toxicity weak Streptococcus pneumoniae experiments on rats. He has pod after killing bacteria with high temperature and no pods with live bacteria injected into mice, and he soon found that mice were killed, while the blood from his rat isolated from the live bacteria have dioxin. This shows that even without pods of dioxins from the dead bacteria have obtained material so that no dioxin into a pod of bacteria. This assumption is correct? Griffith also done experiments in the test tube and found that the death of the US with live bacteria without passing on the tube train at the same time, without all of pods into a pod bacteria, and found that the length of a pod proteins dioxin is a pod of dead carcasses left in nucleic acids (as in the heating of dioxin in the nucleic acid has not been damaged). Griffith said the DNA "conversion factor."
1944, the United States Xijunhuajiaaifuli (1877 - 1955) from the US bacteria isolated from the activity of "conversion factor", and this kind of material to the existence of the protein test pilot, the results are negative, and that "conversion factor" is the DNA. However, this discovery has not been widely recognized, then the technical people can not be suspected in addition to net protein, a protein residues into effect.
American scientists Delbrück Germany (1906 - 1981) phage group Aifuli firmly believe in the discovery. Because they are under electron microscopy to the form and enter the phage the growth of E. coli. Bacterial cells phage is a virus host, and individual small, only by electron microscope to see it. It is like a small tadpole, the external component is the first membrane protein and a tail sheath, the first internal contain DNA, on the tail end of silk sheath, the substrate and small hooks. When the phage infection E. coli, the first cherish in the tail end of the bacterial cell membrane, and then it all in the DNA injected into bacteria cells to the protein shell remain in the bacterial cell outside, then did not play a role in what . Bacterial cells enter the phage DNA, on the use of bacterial phage material rapid synthesis of DNA and proteins, which many copy with the original phage exactly the same size, shape new phage until the bacteria are completely disintegrated, leaving only these phage dead bacteria, go other bacterial infection.
In 1952, key members of phage group Hershey (1908) and his students Chase isotope labeled with advanced technologies in phage infection E. coli experiments. He E. coli T2 phage DNA marker 32 on the P protein shell markings on the 35 S. Marking the first use of T2 phage infection E. coli, and then be separated from the results of phage 35 S will be marked with shell stay outside in E. coli, only with the internal 32 P phage DNA markers all Notes Escherichia coli, E. coli, and the successful conduct of phage reproduction. This experiment proved that DNA is the genetic information transfer function, and proteins from the instructions of the DNA. This result immediately accepted by the academic community.
Almost at the same time, Austria biochemists investigation Mrs. (1905 -) on the four kinds of nucleic acid bases in the content of the re-determination has been fruitful. Aifuli in the impact of the work, he opined that if different kinds of DNA is due to the different, the structure of DNA must be very complicated, otherwise it is difficult to adapt to biological diversity. Therefore, he set out on the text of the "four nucleotide hypothesis" had suspected. In 1948 - 1952 the four-year period, he used more than in the era of precision paper chromatography separation four kinds of bases, UV absorption spectra to do quantitative analysis, after many repeated experiments, they finally come to a different out text results. The experimental results show that, in the DNA macromolecules in the purine and pyrimidine equal to the total number of elements, including adenovirus purine A and the same number of T thymine, birds purine G equal to the number of C and cytosine. DNA molecules in the base of A and T, G and C pair exist, thus negating the "four nucleotide hypothesis", as well as exploring molecular structure of DNA provides an important clue and a basis.
April 25, 1953, Britain's "Nature" magazine published in the Watson of the United States and the United Kingdom Kerik cooperation of the University of Cambridge in the United Kingdom research results: the double helix structure of DNA molecular model, which was later known as the results 20 Biological aspects of the past century's greatest discoveries, marking the birth of molecular biology.
Watson (1928) in the secondary school age is an extremely intelligent child, 15-year-old when they entered the University of Chicago study. At that time, due to an earlier permit experimental studies of sex education programme to Watson the opportunity to pursue all aspects of the integrity of the biological sciences courses. At the university, although Watson in genetics little formal training, but since reading Schrodinger settlement "What is Life? -- The physical appearance of living cells, "which led him to" find genetic secrets. " He was good at brainstorming and gaining public long, good at using other people's ideas to enrich themselves. As long as the conditions to facilitate access, not force yourself to learn a whole new area, can also be required knowledge. 22-year-old Watson, and received a doctorate, and then was sent to Europe to study postdoctoral fellows. In order to fully understand a gene's chemical structure of the virus, he went to study chemical laboratories in Copenhagen, Denmark. Once he went to Naples, Italy, mentors participate in a meeting of biological macromolecules, and the United Kingdom have the opportunity to listen to the physical biologists Wilkins (1916 -)'s speech, Wilkins saw the DNAX-ray diffraction photos. Since then, the search for the key to solve the structure of DNA in the idea in the minds of Watson recovered. Where can I study of X-ray diffraction pattern? So he went to the University of Cambridge Cavendish Laboratory study, in the meantime Watson understanding Kerik.
Kerik (1916) on the passion of science and secondary schools, graduated from the University of London in 1937. In 1946, he read the "What is Life? -- The physical appearance of living cells, "a book for the knowledge of physics to biology to the study of biology from an interest. In 1947 he began graduate to the study, in 1949 he Peiluci together with the use of X-ray technology research protein molecular structure, and Watson was in a meeting. Kerik time than the 12-year-old Watson, the lack of a doctorate. But they talked very speculative, Watson was here even know how to find a DNA protein is more important than the people who really Sanshengweinie. Watson at the same time he was in contact with the people, Kerik is the most intelligent one. They talk at least a few hours every day to discuss academic issues. Two complementary and mutual criticism and stimulate each other's inspiration. They believe that the molecular structure of DNA resolved to open the mystery of the genetic key. Only through the use of precision X-ray diffraction data can be more quickly identify the structure of DNA. In order to be made into DNAX-ray diffraction data, Crick invited Wilkins to Cambridge for the weekend. In conversation Wilkins accepted the spiral structure of DNA is the view also talked about his collaborators Franklin (1920 - 1958, female) as well as laboratory scientists, but also hard thinking model of the structure of DNA problems. From November 1951 to April 1953 18 months, Watson, Crick and Wilkins, Franklin and had several important academic exchanges.
In November 1951, after listening to Franklin Watson on the structure of DNA more detailed report, inspired by a certain knowledge of the crystal structure of Watson and Crick realized that in order to quickly establish DNA structure model only others use the analysis of data. They soon put forward a three helix structure of DNA envisaged. By the end of 1951, they invited Wilkins and Franklin to discuss this model, Franklin pointed out that the DNA in their calculations half less water content, so the establishment of the first model ended in failure.
One day, Watson and Wilkins to the laboratory at King's College, Franklin Wilkins recent shoot out a system of "B" DNA X-ray diffraction photos. Watson see photo, immediately excited, and also speed up the heartbeat, because this image than in the past been "A" much simpler, as long as a little look at the "B" of the X-ray diffraction photos, then by simple calculation, DNA molecules can be identified with more than the number of nucleotide chains.
Please help mathematicians Kerik, the results showed that the source of Yin attractive pyrimidine trend. According to the results of their investigations from Colombo and got the DNA of the two purine and pyrimidine 2 February 2 equal results, and formed a base pairing concept.
They hard to think of the four kinds of bases order, again and again in the base structure-paper painting, playing with model assumptions made time and time again, and again, to overthrow their own assumptions.
On one occasion, Watson also playing with the idea on its own model, he shifted base to remove the possibility of looking for a variety of matching. All of a sudden, he found that two hydrogen bonds connect the gland fat-yin, and even for a thymidine by three hydrogen bonds linking the birds allopurinol Ridge on a cytosine have the same shape, it was the spirit of his colleagues. Because of the number of purine and pyrimidine why the number was identical to this mystery solved. Mrs. investigation of all of a sudden it became DNA double helix structure of the inevitable result. Therefore, how a chain as a separate template synthesis of the complementary base sequence is not hard to imagine the chain. Well, two of the skeleton chain must be in the opposite direction.
After Watson and Crick continuous tension, quickly completed DNA metal model assembly. From this model that linked DNA from two nucleotide composition, along the central axis them to the opposite direction entwined each other, much like a spiral staircases, handrails on both sides is more than two nucleotide chain P gene sugar alternately with a skeleton, and pedal base is right. In the absence of accurate information on the X-ray, they also concluded that model is not entirely correct.
The next step is the scientific method to predict the basis of this model of the X-ray diffraction pattern with the experimental data for some serious comparison. They called once again invited Wilkins. Less than two days of work, Wilkins and Franklin used X-ray data analysis confirmed the double helix structure of the model is correct, and wrote a report also published two experiments in the United Kingdom "Nature" magazine. 1962, Watson, Crick and Wilkins received the Nobel Prize in Physiology and Medicine, and Franklin died of cancer death in 1958 and had not been granted the award.
Towards the late 1930s, Sweden's scientists to prove that DNA is symmetrical. After World War II, using electron microscopy of the DNA molecule is about 2 nm in diameter.
The double helix structure of DNA was discovered, greatly shocked the academia, inspiring people's minds. Since then, people immediately genetics for the Centre carried out a large number of molecular biology research. The first is around the four kinds of bases to encode what permutations and combinations can be expressed as 20 kinds of amino acids centres studied. 1967, the genetic code was cracked all the genes in the DNA molecular level so as to achieve new concept. It shows that: DNA gene is actually a fragment of macromolecules is controlling biological traits of the functional units of genetic material and structural units. In this unit on a number of nucleotide fragment is not arbitrary arrangement, but so as to the meaning of the password order. Some of the DNA structure can be controlled synthesis of the corresponding proteins. Protein is an important component of organisms, the organisms is mainly through the characters to reflect the protein. Therefore, the control of gene traits through DNA control protein synthesis. On this basis, have had a genetic engineering, enzyme engineering, fermentation engineering, protein engineering, biotechnology development will make use of the people of the benefit of mankind. The development of modern biology, more shows will lead to increased discipline for the trend.
Since the Mendelian genetic law was rediscovered after, it has raised a question: genetic factor is not a material entity? In order to address the question of what genes are, people are starting to nucleic acid and protein research.
As early as 1868, people had discovered the DNA. German chemist in the laboratory Hepei Le, a graduate Mingjiaomixieer Swiss (1844 - 1895), his laboratory near a hospital threw a bandage with a flu Nongxue interested, because he knows that in order to defend those Nongxie human health and disease " 'operations," and died in the WBC and the human cells were killed "remains." So he carefully bandage on the Nongxue collection, and using pepsin to break it down, found the bodies of most of the cell decomposition, but the nuclear non-functional. He further analysis of nucleus material found in the nucleus containing a phosphorus and nitrogen-rich material. Hepei Le experiments with yeast, that the nucleus of Michel substances found to be correct. So he would give such nuclei isolated from the material named "radionuclide", but found it was acidic and therefore diverted called "nucleic acids." Since then people have carried out a series of effective nucleic acid research.
In the early 20th century, Germany Kesaier (1853 - 1927) and two of his students Jones (1865 - 1935) and in the text (1869 - 1940) study, made clear the basic chemical structure of DNA, that it Nucleotide is composed of many macromolecules. By the nucleotide bases, consisting of phosphate and ribose. There are four kinds of bases (adeno-Piao Yin, the birds purine, thymine and cytosine), there are two ribose (ribosomes, deoxyribose), the nucleic acid into ribonucleic acid (RNA) and deoxyribonucleic acid ( DNA).
In a hurry to the text of his research results, erroneously think that the four kinds of bases in DNA is in the amount equal to nucleic acids derived from the basic structure of four nucleotide bases with different connections into the four nucleosides Acid as a basis for a nucleic acid polymer, proposed a "four nucleotide hypothesis." This hypothesis wrong, the understanding of the complexity of DNA structure considerable impediment, to a certain extent, affected the people's understanding of the function of nucleic acids. It was felt that although the nucleic acid present in the structure of the important - the nucleus, but its structure is too simple, it is difficult to envisage it in the genetic processes in what role.
Protein than the discovery of DNA as early as 30, have developed rapidly. The beginning of the 20th century, composed of 20 kinds of amino acid protein of 12 species have been found, in 1940, all were found.
1902, a German chemist for Xieerchi between amino acid peptide chain connected to the formation of protein theory, in 1917 he was synthesized from 15 glycine and three leucine composed of 18 long-chain peptide . Therefore, the idea of some scientists is possible that the genetic proteins play a major role. If the nucleic acid involved in genetic role, but also must be linked with the protein in the NP role. Therefore, when biological protein is generally inclined to think that the carrier of genetic information.
1928, the United States scientists Griffith (1877 - 1941) in an Clostridium perfringens, and a toxic-free capsule, toxicity weak Streptococcus pneumoniae experiments on rats. He has pod after killing bacteria with high temperature and no pods with live bacteria injected into mice, and he soon found that mice were killed, while the blood from his rat isolated from the live bacteria have dioxin. This shows that even without pods of dioxins from the dead bacteria have obtained material so that no dioxin into a pod of bacteria. This assumption is correct? Griffith also done experiments in the test tube and found that the death of the US with live bacteria without passing on the tube train at the same time, without all of pods into a pod bacteria, and found that the length of a pod proteins dioxin is a pod of dead carcasses left in nucleic acids (as in the heating of dioxin in the nucleic acid has not been damaged). Griffith said the DNA "conversion factor."
1944, the United States Xijunhuajiaaifuli (1877 - 1955) from the US bacteria isolated from the activity of "conversion factor", and this kind of material to the existence of the protein test pilot, the results are negative, and that "conversion factor" is the DNA. However, this discovery has not been widely recognized, then the technical people can not be suspected in addition to net protein, a protein residues into effect.
American scientists Delbrück Germany (1906 - 1981) phage group Aifuli firmly believe in the discovery. Because they are under electron microscopy to the form and enter the phage the growth of E. coli. Bacterial cells phage is a virus host, and individual small, only by electron microscope to see it. It is like a small tadpole, the external component is the first membrane protein and a tail sheath, the first internal contain DNA, on the tail end of silk sheath, the substrate and small hooks. When the phage infection E. coli, the first cherish in the tail end of the bacterial cell membrane, and then it all in the DNA injected into bacteria cells to the protein shell remain in the bacterial cell outside, then did not play a role in what . Bacterial cells enter the phage DNA, on the use of bacterial phage material rapid synthesis of DNA and proteins, which many copy with the original phage exactly the same size, shape new phage until the bacteria are completely disintegrated, leaving only these phage dead bacteria, go other bacterial infection.
In 1952, key members of phage group Hershey (1908) and his students Chase isotope labeled with advanced technologies in phage infection E. coli experiments. He E. coli T2 phage DNA marker 32 on the P protein shell markings on the 35 S. Marking the first use of T2 phage infection E. coli, and then be separated from the results of phage 35 S will be marked with shell stay outside in E. coli, only with the internal 32 P phage DNA markers all Notes Escherichia coli, E. coli, and the successful conduct of phage reproduction. This experiment proved that DNA is the genetic information transfer function, and proteins from the instructions of the DNA. This result immediately accepted by the academic community.
Almost at the same time, Austria biochemists investigation Mrs. (1905 -) on the four kinds of nucleic acid bases in the content of the re-determination has been fruitful. Aifuli in the impact of the work, he opined that if different kinds of DNA is due to the different, the structure of DNA must be very complicated, otherwise it is difficult to adapt to biological diversity. Therefore, he set out on the text of the "four nucleotide hypothesis" had suspected. In 1948 - 1952 the four-year period, he used more than in the era of precision paper chromatography separation four kinds of bases, UV absorption spectra to do quantitative analysis, after many repeated experiments, they finally come to a different out text results. The experimental results show that, in the DNA macromolecules in the purine and pyrimidine equal to the total number of elements, including adenovirus purine A and the same number of T thymine, birds purine G equal to the number of C and cytosine. DNA molecules in the base of A and T, G and C pair exist, thus negating the "four nucleotide hypothesis", as well as exploring molecular structure of DNA provides an important clue and a basis.
April 25, 1953, Britain's "Nature" magazine published in the Watson of the United States and the United Kingdom Kerik cooperation of the University of Cambridge in the United Kingdom research results: the double helix structure of DNA molecular model, which was later known as the results 20 Biological aspects of the past century's greatest discoveries, marking the birth of molecular biology.
Watson (1928) in the secondary school age is an extremely intelligent child, 15-year-old when they entered the University of Chicago study. At that time, due to an earlier permit experimental studies of sex education programme to Watson the opportunity to pursue all aspects of the integrity of the biological sciences courses. At the university, although Watson in genetics little formal training, but since reading Schrodinger settlement "What is Life? -- The physical appearance of living cells, "which led him to" find genetic secrets. " He was good at brainstorming and gaining public long, good at using other people's ideas to enrich themselves. As long as the conditions to facilitate access, not force yourself to learn a whole new area, can also be required knowledge. 22-year-old Watson, and received a doctorate, and then was sent to Europe to study postdoctoral fellows. In order to fully understand a gene's chemical structure of the virus, he went to study chemical laboratories in Copenhagen, Denmark. Once he went to Naples, Italy, mentors participate in a meeting of biological macromolecules, and the United Kingdom have the opportunity to listen to the physical biologists Wilkins (1916 -)'s speech, Wilkins saw the DNAX-ray diffraction photos. Since then, the search for the key to solve the structure of DNA in the idea in the minds of Watson recovered. Where can I study of X-ray diffraction pattern? So he went to the University of Cambridge Cavendish Laboratory study, in the meantime Watson understanding Kerik.
Kerik (1916) on the passion of science and secondary schools, graduated from the University of London in 1937. In 1946, he read the "What is Life? -- The physical appearance of living cells, "a book for the knowledge of physics to biology to the study of biology from an interest. In 1947 he began graduate to the study, in 1949 he Peiluci together with the use of X-ray technology research protein molecular structure, and Watson was in a meeting. Kerik time than the 12-year-old Watson, the lack of a doctorate. But they talked very speculative, Watson was here even know how to find a DNA protein is more important than the people who really Sanshengweinie. Watson at the same time he was in contact with the people, Kerik is the most intelligent one. They talk at least a few hours every day to discuss academic issues. Two complementary and mutual criticism and stimulate each other's inspiration. They believe that the molecular structure of DNA resolved to open the mystery of the genetic key. Only through the use of precision X-ray diffraction data can be more quickly identify the structure of DNA. In order to be made into DNAX-ray diffraction data, Crick invited Wilkins to Cambridge for the weekend. In conversation Wilkins accepted the spiral structure of DNA is the view also talked about his collaborators Franklin (1920 - 1958, female) as well as laboratory scientists, but also hard thinking model of the structure of DNA problems. From November 1951 to April 1953 18 months, Watson, Crick and Wilkins, Franklin and had several important academic exchanges.
In November 1951, after listening to Franklin Watson on the structure of DNA more detailed report, inspired by a certain knowledge of the crystal structure of Watson and Crick realized that in order to quickly establish DNA structure model only others use the analysis of data. They soon put forward a three helix structure of DNA envisaged. By the end of 1951, they invited Wilkins and Franklin to discuss this model, Franklin pointed out that the DNA in their calculations half less water content, so the establishment of the first model ended in failure.
One day, Watson and Wilkins to the laboratory at King's College, Franklin Wilkins recent shoot out a system of "B" DNA X-ray diffraction photos. Watson see photo, immediately excited, and also speed up the heartbeat, because this image than in the past been "A" much simpler, as long as a little look at the "B" of the X-ray diffraction photos, then by simple calculation, DNA molecules can be identified with more than the number of nucleotide chains.
Please help mathematicians Kerik, the results showed that the source of Yin attractive pyrimidine trend. According to the results of their investigations from Colombo and got the DNA of the two purine and pyrimidine 2 February 2 equal results, and formed a base pairing concept.
They hard to think of the four kinds of bases order, again and again in the base structure-paper painting, playing with model assumptions made time and time again, and again, to overthrow their own assumptions.
On one occasion, Watson also playing with the idea on its own model, he shifted base to remove the possibility of looking for a variety of matching. All of a sudden, he found that two hydrogen bonds connect the gland fat-yin, and even for a thymidine by three hydrogen bonds linking the birds allopurinol Ridge on a cytosine have the same shape, it was the spirit of his colleagues. Because of the number of purine and pyrimidine why the number was identical to this mystery solved. Mrs. investigation of all of a sudden it became DNA double helix structure of the inevitable result. Therefore, how a chain as a separate template synthesis of the complementary base sequence is not hard to imagine the chain. Well, two of the skeleton chain must be in the opposite direction.
After Watson and Crick continuous tension, quickly completed DNA metal model assembly. From this model that linked DNA from two nucleotide composition, along the central axis them to the opposite direction entwined each other, much like a spiral staircases, handrails on both sides is more than two nucleotide chain P gene sugar alternately with a skeleton, and pedal base is right. In the absence of accurate information on the X-ray, they also concluded that model is not entirely correct.
The next step is the scientific method to predict the basis of this model of the X-ray diffraction pattern with the experimental data for some serious comparison. They called once again invited Wilkins. Less than two days of work, Wilkins and Franklin used X-ray data analysis confirmed the double helix structure of the model is correct, and wrote a report also published two experiments in the United Kingdom "Nature" magazine. 1962, Watson, Crick and Wilkins received the Nobel Prize in Physiology and Medicine, and Franklin died of cancer death in 1958 and had not been granted the award.
Towards the late 1930s, Sweden's scientists to prove that DNA is symmetrical. After World War II, using electron microscopy of the DNA molecule is about 2 nm in diameter.
The double helix structure of DNA was discovered, greatly shocked the academia, inspiring people's minds. Since then, people immediately genetics for the Centre carried out a large number of molecular biology research. The first is around the four kinds of bases to encode what permutations and combinations can be expressed as 20 kinds of amino acids centres studied. 1967, the genetic code was cracked all the genes in the DNA molecular level so as to achieve new concept. It shows that: DNA gene is actually a fragment of macromolecules is controlling biological traits of the functional units of genetic material and structural units. In this unit on a number of nucleotide fragment is not arbitrary arrangement, but so as to the meaning of the password order. Some of the DNA structure can be controlled synthesis of the corresponding proteins. Protein is an important component of organisms, the organisms is mainly through the characters to reflect the protein. Therefore, the control of gene traits through DNA control protein synthesis. On this basis, have had a genetic engineering, enzyme engineering, fermentation engineering, protein engineering, biotechnology development will make use of the people of the benefit of mankind. The development of modern biology, more shows will lead to increased discipline for the trend.
[DNA] [Distribution] and function
[DNA] [Distribution] and function
Prokaryotic cell chromosome is a long DNA molecule. Eukaryotic cells in more than one chromosome, chromosome each containing only a DNA molecule. But they generally than prokaryotic cells in the DNA and protein molecules and large combination. DNA molecules function is the storage of all species decision protein and RNA structure all the genetic information; orderly planning of biological cells and tissue components of time and space; identified throughout the life cycle of the biological activity and define the personality. In addition to chromosomal DNA, a very small amount of DNA found in different eukaryotic cells in the mitochondria and chloroplasts. DNA is the genetic material of the virus DNA.
Prokaryotic cell chromosome is a long DNA molecule. Eukaryotic cells in more than one chromosome, chromosome each containing only a DNA molecule. But they generally than prokaryotic cells in the DNA and protein molecules and large combination. DNA molecules function is the storage of all species decision protein and RNA structure all the genetic information; orderly planning of biological cells and tissue components of time and space; identified throughout the life cycle of the biological activity and define the personality. In addition to chromosomal DNA, a very small amount of DNA found in different eukaryotic cells in the mitochondria and chloroplasts. DNA is the genetic material of the virus DNA.
[DNA] the physical and chemical properties
[DNA] the physical and chemical properties
DNA is macromolecular polymers, DNA solution for the polymer solution with very high viscosity. DNA absorption of UV radiation, when DNA denaturation, the absorption value increased when the degeneration of the nucleic acid can be reused, absorption values will be restored to the original level. Temperature, the organic solvent, pH, urea, amides such as reagents DNA molecules can be caused degeneration, even in the DNA double bond between the hydrogen bond breaking double helix structure untied.
DNA (deoxyribonucleic acid) that DNA (chromosomes and genes component) deoxynucleotidyl the polymer, chromosome is the main ingredients. The vast majority of the genetic information stored in DNA molecules.
DNA is macromolecular polymers, DNA solution for the polymer solution with very high viscosity. DNA absorption of UV radiation, when DNA denaturation, the absorption value increased when the degeneration of the nucleic acid can be reused, absorption values will be restored to the original level. Temperature, the organic solvent, pH, urea, amides such as reagents DNA molecules can be caused degeneration, even in the DNA double bond between the hydrogen bond breaking double helix structure untied.
DNA (deoxyribonucleic acid) that DNA (chromosomes and genes component) deoxynucleotidyl the polymer, chromosome is the main ingredients. The vast majority of the genetic information stored in DNA molecules.
DNA [Structures]
DNA [Structures]
DNA is composed of many deoxynucleotidyl residues each other with a certain amount of order 3 ', 5'-phosphate ester bond linked to a long chain. Most of DNA containing two such long-chain, and some are single DNA chain, such as E. coli φ X174 bacteriophage, G4, such as M13. Some DNA for the ring, and some of linear DNA. Main contain adenine, guanine, thymine and cytosine four kinds of bases. In certain types of DNA, 5 - methylcytosine within certain limits can be replaced by cytosine, which the wheat germ DNA 5 - methylcytosine particularly rich, Moore is 6%. In some phage, 5 - hydroxymethyl-cytosine replaced cytosine. 40 late 1990s, Mrs. investigation (E. Chargaff) found that different species of DNA base composition different, but equivalent to the number of its thymine adenine (A = T), cytosine guanine few equivalent ( G = C), thus the number of purine and pyrimidine equivalent to the sum of the number. Several described by the general level of the structure of DNA.
A structure of a DNA structure that is the sequence. Gene is a fragment of DNA, the genetic information stored in their genetic sequence of. 1975 United States Gilbert (W. Gilbert) and the United Kingdom's Sanger (F. Sanger) were the creation of a DNA structure of the rapid determination of their total for the year 1980 Nobel Prize in Chemistry. Since then, determination and constantly improved, many of the level structure of DNA has been established. If people ring of mitochondrial DNA containing 16,569 base pairs, λ phage DNA containing 48,502 base pairs, rice chloroplast genome of 134,525 base pairs, tobacco chloroplast genome of 155,844 base pairs, etc.. Now the United States has plans to 10 to 15 years in all of human DNA molecule of about 3 billion nucleotide sequencing out of.
Secondary structure in 1953, Watson (Watson) and Crick (Crick) of the basic structure of DNA fibers is the double helix structure of this model was recognized by scientists, and to explain replication, transcription, and other important life process. After in-depth study and found that due to humidity and different conditions, such as sequence, DNA double helix can have many types, mainly divided into A, B and Z3 major categories.
Generally believed that the nearest B configuration of the DNA in cells of conformation, and the double helix model it is very similar. A-DNA and RNA molecules in the area, as well as the double helix of DNA was formed in transcription-RNA hybrid molecular conformation close. Z-DNA nucleotide dimer in the unit left to the wound, its main chain were serrated (Z)-, Gu Ming. This configuration suitable for multi-pyrimidine nucleotides chain of alternating purine District. 1989, the United States scientists using scanning tunneling electron microscope to directly observe the DNA double helix DNA double helix: in 1952, Austria-American biochemists search Jiafu (E.chargaff, 1905 -) Determination of the DNA of the four kinds of bases Content found gland fat methotrexate and the same number of thymine, cytosine birds fat and the number of methotrexate equal. This makes Watson, Crick immediately think of four kinds of bases exist between February 2 corresponding relations, and formed a gland fat methotrexate paired with thymine, cytosine and bird fat methotrexate matching concept.
February 1953, Watson, Crick saw through Weierjinshi Franklin in November 1951 shooting of a very beautiful DNA crystal X-ray diffraction photos, to stimulate their inspiration. They not only confirmed the DNA helix structure is certain, and that the spiral of parameters. They used the rich Lankelin and Wilkins judgement, and to add: phosphate in a spiral of more than two lateral nucleotide chain skeleton, the opposite direction; base in the inner spiral, February 2 counterparts.
Over the past few days, Watson and Crick in their offices happily with a tin and wire model structures. February 28, 1953, a DNA double helix structure of the molecular model was born.
Double helix model of significance, not only proven means that the structure of the DNA molecule, it is more important that a mechanism of DNA replication: As always with methotrexate gland fat thymidine matching, the birds fat methotrexate always paired with cytosine This shows that the two chains base sequence complementary to each other, identified as one of the nucleotide sequence chain, another chain will determine the base sequence. Therefore, only one of them linked to the template can be copied to another of a chain.
Kerik from the beginning to insist that in the April 25 papers published in the "specific DNA matching principle, immediately reminiscent of genetic material may have to copy mechanisms" such a statement. He believes that if no such sentence would mean he and Watson "lack of insight, which can not be seen to this point."
In a DNA double helix structure papers shortly after, the "natural" Shortly afterward magazine also published a paper Kerik another, a semi-stated reservations DNA replication mechanism.
DNA is composed of many deoxynucleotidyl residues each other with a certain amount of order 3 ', 5'-phosphate ester bond linked to a long chain. Most of DNA containing two such long-chain, and some are single DNA chain, such as E. coli φ X174 bacteriophage, G4, such as M13. Some DNA for the ring, and some of linear DNA. Main contain adenine, guanine, thymine and cytosine four kinds of bases. In certain types of DNA, 5 - methylcytosine within certain limits can be replaced by cytosine, which the wheat germ DNA 5 - methylcytosine particularly rich, Moore is 6%. In some phage, 5 - hydroxymethyl-cytosine replaced cytosine. 40 late 1990s, Mrs. investigation (E. Chargaff) found that different species of DNA base composition different, but equivalent to the number of its thymine adenine (A = T), cytosine guanine few equivalent ( G = C), thus the number of purine and pyrimidine equivalent to the sum of the number. Several described by the general level of the structure of DNA.
A structure of a DNA structure that is the sequence. Gene is a fragment of DNA, the genetic information stored in their genetic sequence of. 1975 United States Gilbert (W. Gilbert) and the United Kingdom's Sanger (F. Sanger) were the creation of a DNA structure of the rapid determination of their total for the year 1980 Nobel Prize in Chemistry. Since then, determination and constantly improved, many of the level structure of DNA has been established. If people ring of mitochondrial DNA containing 16,569 base pairs, λ phage DNA containing 48,502 base pairs, rice chloroplast genome of 134,525 base pairs, tobacco chloroplast genome of 155,844 base pairs, etc.. Now the United States has plans to 10 to 15 years in all of human DNA molecule of about 3 billion nucleotide sequencing out of.
Secondary structure in 1953, Watson (Watson) and Crick (Crick) of the basic structure of DNA fibers is the double helix structure of this model was recognized by scientists, and to explain replication, transcription, and other important life process. After in-depth study and found that due to humidity and different conditions, such as sequence, DNA double helix can have many types, mainly divided into A, B and Z3 major categories.
Generally believed that the nearest B configuration of the DNA in cells of conformation, and the double helix model it is very similar. A-DNA and RNA molecules in the area, as well as the double helix of DNA was formed in transcription-RNA hybrid molecular conformation close. Z-DNA nucleotide dimer in the unit left to the wound, its main chain were serrated (Z)-, Gu Ming. This configuration suitable for multi-pyrimidine nucleotides chain of alternating purine District. 1989, the United States scientists using scanning tunneling electron microscope to directly observe the DNA double helix DNA double helix: in 1952, Austria-American biochemists search Jiafu (E.chargaff, 1905 -) Determination of the DNA of the four kinds of bases Content found gland fat methotrexate and the same number of thymine, cytosine birds fat and the number of methotrexate equal. This makes Watson, Crick immediately think of four kinds of bases exist between February 2 corresponding relations, and formed a gland fat methotrexate paired with thymine, cytosine and bird fat methotrexate matching concept.
February 1953, Watson, Crick saw through Weierjinshi Franklin in November 1951 shooting of a very beautiful DNA crystal X-ray diffraction photos, to stimulate their inspiration. They not only confirmed the DNA helix structure is certain, and that the spiral of parameters. They used the rich Lankelin and Wilkins judgement, and to add: phosphate in a spiral of more than two lateral nucleotide chain skeleton, the opposite direction; base in the inner spiral, February 2 counterparts.
Over the past few days, Watson and Crick in their offices happily with a tin and wire model structures. February 28, 1953, a DNA double helix structure of the molecular model was born.
Double helix model of significance, not only proven means that the structure of the DNA molecule, it is more important that a mechanism of DNA replication: As always with methotrexate gland fat thymidine matching, the birds fat methotrexate always paired with cytosine This shows that the two chains base sequence complementary to each other, identified as one of the nucleotide sequence chain, another chain will determine the base sequence. Therefore, only one of them linked to the template can be copied to another of a chain.
Kerik from the beginning to insist that in the April 25 papers published in the "specific DNA matching principle, immediately reminiscent of genetic material may have to copy mechanisms" such a statement. He believes that if no such sentence would mean he and Watson "lack of insight, which can not be seen to this point."
In a DNA double helix structure papers shortly after, the "natural" Shortly afterward magazine also published a paper Kerik another, a semi-stated reservations DNA replication mechanism.
Untie the secret [DNA]
Untie the secret [DNA]
When the gene is found DNA, people still would like to know how this DNA is a kind of things, it is through what specific way to the lives of so many messages to the new successor?
First people would like to know what DNA is composed of human love is always asked at the end of this plane. The results have a called Ryun scientists through research, found that DNA is from four smaller things component, the total of these four things named nucleotides, as the four brothers, they are both named nucleotide, but name is different, namely adenine (A), guanine (G), cytosine (C) and thymine (T), which are difficult to remember names, but as long as the DNA is from four to remember nucleotides only casually together, and their mutual connection there is no law, but later nucleotide in fact not the same, but they are interconnected combination of changing the way great mysteries. Now, the people have to understand the genetic basically how it happened. Studies on the biology of the 20th century discovery: the body from cells, and cells from the cell membrane, cytoplasm and nucleus formed. Known in the nucleus in a substance called chromosomes, some called it mainly by the deoxyribonucleic acid (DNA) of the material.
Of the genetic material found in all cells, this kind of material called RNA. DNA from the nucleotide polymerization. And each nucleotide phosphate, ribose and a base. There are five bases, respectively adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U). Each contains only the five nucleotide bases in kind.
Single nucleotide linked together into one, two nucleotide chain at a certain order, and then twisted into a "Serratula" sample, a deoxyribonucleic acid (DNA) of the molecular structure. In this structure, each composed of three base pairs can be a genetic "password" and a DNA, as many as several million base pairs, each of the DNA is a genetic code greatly this, the inside of the genetic information countless more of this DNA molecule exists in the nucleus on the chromosomes. They will be split with the transfer of genetic code.
The genetic traits to be passed by password. Probably have 25,000 genes, and each gene is by password to decide. The same gene in both parts have different parts. Different people different from some of its decisions, that is, human diversity. A total of 3 billion DNA genetic code, are composed of about 25,000 genes.
When the gene is found DNA, people still would like to know how this DNA is a kind of things, it is through what specific way to the lives of so many messages to the new successor?
First people would like to know what DNA is composed of human love is always asked at the end of this plane. The results have a called Ryun scientists through research, found that DNA is from four smaller things component, the total of these four things named nucleotides, as the four brothers, they are both named nucleotide, but name is different, namely adenine (A), guanine (G), cytosine (C) and thymine (T), which are difficult to remember names, but as long as the DNA is from four to remember nucleotides only casually together, and their mutual connection there is no law, but later nucleotide in fact not the same, but they are interconnected combination of changing the way great mysteries. Now, the people have to understand the genetic basically how it happened. Studies on the biology of the 20th century discovery: the body from cells, and cells from the cell membrane, cytoplasm and nucleus formed. Known in the nucleus in a substance called chromosomes, some called it mainly by the deoxyribonucleic acid (DNA) of the material.
Of the genetic material found in all cells, this kind of material called RNA. DNA from the nucleotide polymerization. And each nucleotide phosphate, ribose and a base. There are five bases, respectively adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U). Each contains only the five nucleotide bases in kind.
Single nucleotide linked together into one, two nucleotide chain at a certain order, and then twisted into a "Serratula" sample, a deoxyribonucleic acid (DNA) of the molecular structure. In this structure, each composed of three base pairs can be a genetic "password" and a DNA, as many as several million base pairs, each of the DNA is a genetic code greatly this, the inside of the genetic information countless more of this DNA molecule exists in the nucleus on the chromosomes. They will be split with the transfer of genetic code.
The genetic traits to be passed by password. Probably have 25,000 genes, and each gene is by password to decide. The same gene in both parts have different parts. Different people different from some of its decisions, that is, human diversity. A total of 3 billion DNA genetic code, are composed of about 25,000 genes.
DNA Features
[DNA Features
A. DNA from the monomer polymerization deoxynucleotidyl from the polymer.
B. DNA monomer called deoxynucleotidyl, each deoxynucleotidyl composed of three parts: part of the five members of nitrogen bases + carbon sugar (deoxyribose) + member phosphate, DNA by C, H, O, N, P composed of five elements.
C. DNA nitrogen base can be divided into four categories: guanine (Guanine), thymine (Thymine), adenine (Adenine), cytosine (Cytosine)
D. DNA sequence of the four kinds of nitrogen species specificity. That the ratio of four nitrogen-containing bases in the same species, different individuals is the same, but in different species there are differences.
E. DNA ratio of four nitrogen-containing bases with unusual regularity, and each organism DNA of A (adenine deoxynucleotidyl) = T (thymine deoxynucleotidyl) C (cytosine deoxy Nucleotide) = G (guanine deoxynucleotidyl). A and T hydrogen bonds between the two linked, C and G to three hydrogen bonds between connected.
A. DNA from the monomer polymerization deoxynucleotidyl from the polymer.
B. DNA monomer called deoxynucleotidyl, each deoxynucleotidyl composed of three parts: part of the five members of nitrogen bases + carbon sugar (deoxyribose) + member phosphate, DNA by C, H, O, N, P composed of five elements.
C. DNA nitrogen base can be divided into four categories: guanine (Guanine), thymine (Thymine), adenine (Adenine), cytosine (Cytosine)
D. DNA sequence of the four kinds of nitrogen species specificity. That the ratio of four nitrogen-containing bases in the same species, different individuals is the same, but in different species there are differences.
E. DNA ratio of four nitrogen-containing bases with unusual regularity, and each organism DNA of A (adenine deoxynucleotidyl) = T (thymine deoxynucleotidyl) C (cytosine deoxy Nucleotide) = G (guanine deoxynucleotidyl). A and T hydrogen bonds between the two linked, C and G to three hydrogen bonds between connected.
DNA
Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. The main role of DNA is the lon-term storage of information and it is often compared to a set of blueprints, since DNA contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information.
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