Keywords: Human Genome Project
Text:
human genome project
The Human Genome Project was put forward in 1980s. International cooperation organizations, including the United States, Britain, Japan, China, Germany and France, participated in the mapping of the human genome, and determined all the DNA sequences of 23 pairs of human chromosomes consisting of 3× 109 nucleotides. In 2000, the "working frame map" of the human genome was completed. In 200 1 year, the human genome map and preliminary analysis results were published. Its research content also includes establishing a computer analysis management system to test related ethical, legal and social issues, and then analyzing gene expression profiles and gene mutations through transcriptomics and protein genomics, so as to obtain information about disease-related genes. The Human Genome Project, the Manhattan Atomic Bomb Project and the Apollo Project are also called the three major scientific projects.
The human genome project has made great progress in more than 20 years.
The Human Genome Project was first proposed in 1985 by Nobel Prize winner Lei Natuo Durbeck of the United States. The original purpose is to complete the base sequence determination of about 3 billion nucleotides in the human genome, clarify all human genes and determine their positions on chromosomes, so as to decipher all human genetic genes.
1On March 7th, 986, Durbeck published an article entitled "The Turning Point of Cancer Research-Determination of Human Genome Sequence", pointing out that the occurrence of cancer and other diseases is related to genes, and put forward the ways and significance of determining the whole human genome sequence.
1988 The U.S. Department of Energy and the National Institutes of Health led the human genome project in the United States, which was approved by Congress and funded by the government. Since then, an international cooperation organization, the Human Genome Organization, has been established, and many countries have raised funds and scientific research strength to actively participate in this international research project.
1990 5438+00 In June, the International Human Genome Project was officially launched. It is estimated that it will take 15 years to complete the sequencing of 3 billion base pairs, and all the genes (estimated at that time at 80,000 ~ 65,438+million) will be mapped and sequenced. The Global Human Genome Project is under the responsibility of six countries: the United States, Britain, Japan, France, Germany and China. Among them, the United States undertook 54% of all tasks, Britain 33%, Japan 7%, France 2.8%, Germany 2.2%, and China was allowed to join the Human Genome Project in September of 1999, and undertook the sequencing task of 1%, namely chromosome 3 breakage. ?
China started the related research project on 1993, and set up two national human genome centers in Shanghai and Beijing successively, which undertook the task of 1% sequencing in the human genome project. Through the cooperation of scientists from many countries, mankind finally completed its preliminary work of genome sequencing in the 1990s.
In June 2003, scientists from China, the United States, Japan, Germany, France and Britain announced that they had drawn a "working frame map" of the human genome for the first time.
On April 14, 2003, scientists from China, the United States, Japan, Germany, France and Britain announced that the human genome sequence map had been drawn successfully and all the goals of the Human Genome Project had been achieved.
In 2004, the human genome was sequenced;
In 2005, the sequencing of human X chromosome was basically completed, and the sketch of chromosome gene was published.
The main task of HGP is human DNA sequencing, including the four spectrograms shown in the figure below, as well as sequencing technology, human genome sequence variation, functional genome technology, comparative genomics, social, legal and ethical research, bioinformatics and computational biology, education and training.
1, genetic map
Also known as linkage map, it is a map to determine the relative distance and position between genes or genetic markers according to their exchange recombination values on chromosomes. Its graphic distance unit is coml to commemorate Morgan, the founder of modern genetics. The establishment of genetic map creates conditions for gene identification and gene location. Significance: More than 6,000 genetic markers have been able to divide the human genome into more than 6,000 regions, so that linkage analysis can find evidence that a pathogenic or phenotypic gene is close to a marker, so that the gene can be located in this known region, and then the gene can be isolated and studied. For diseases, finding and analyzing genes is a key.
2. Natural map
Physical map refers to the information about the arrangement and spacing of all genes that make up the genome, which is drawn by measuring the DNA molecules that make up the genome. The purpose of drawing physical maps is to arrange the genetic information about genes and their relative positions on each chromosome in a linear system. The physical map of DNA refers to the arrangement order of restriction fragments of DNA chain, that is, the position of restriction fragments on DNA chain. Because restriction endonucleases are based on specific sequences, DNA fragments with different nucleotide sequences will be produced after digestion, thus forming a unique digestion map. Therefore, the physical map of DNA is one of the characteristics of DNA molecular structure. DNA is a very large molecule, and the DNA fragment produced by restriction endonuclease for sequencing reaction is only a very small part of it. The position relationship of these fragments in DNA chain is the first problem to be solved, so the physical map of DNA is the basis of sequence determination and can also be understood as the blueprint to guide DNA sequencing. Broadly speaking, DNA sequencing begins with making physical maps, which is the first step of sequencing. There are many ways to make a physical map of DNA. Here, we choose a common and simple method-partial enzymolysis of labeled fragments to illustrate the drawing principle.
The determination of DNA physical map by partial enzymolysis includes two basic steps: (1) complete degradation; (2) partial degradation.
3. Sequence diagram
With the completion of gene map and physical map, sequencing has become the most important. DNA sequence analysis is a multi-stage process including DNA fragmentation, base analysis and DNA information translation. The sequence map of the genome was obtained by sequencing.
4.DNA map
Gene mapping is based on identifying the protein coding sequence contained in the genome, and combining information such as gene sequence, location and expression pattern. The most important way to identify the position, structure and function of all genes with 2%~5% length in human genome is to trace back to the position of chromosome through mRNA, the expression product of genes.
principle
Significance of gene map
It can effectively reflect the Shi Kongtu of the whole gene expressed under normal or controlled conditions. Through this picture, we can know the expression of a gene in different tissues and levels at different times. We can also know the different expression levels of different genes in a tissue at different times, and we can also know the different expression levels of different genes in different tissues at a specific time.
The implementation of the human genome project is of great significance and far-reaching influence.
First, reveal the history of human development.
The human genome project to decipher the life code is helpful for people to have a deeper understanding of gene expression regulation. At the same time, the human genome map is of great significance to reveal the history of human development and evolution. The study of evolution is no longer based on assumptions. Using comparative genomics to study ancient DNA can reveal the mystery of life evolution and the relationship between ancient and modern organisms, and help people better understand the status of human beings in nature.
Second, gene therapy.
Obtaining all human gene sequences will help people understand the pathogenesis of various genetic diseases and cancers, and provide theoretical basis for new methods such as molecular diagnosis and gene therapy. In the near future, we can know the resistance of different individuals to diseases according to the difference of DNA sequence of each person, and prescribe the right medicine according to everyone's "genetic characteristics", which is the medicine of 2 1 century-individualized medicine. More importantly, gene therapy can not only prevent patients from getting sick in the future, but also prevent their offspring from getting the same disease.
Third, the research of genetically engineered drugs.
Genetically engineered drugs are the expression products of recombinant DNA. Broadly speaking, anything that involves genetic engineering in the process of drug production can become a genetically engineered drug. The application of gene technology in pharmaceutical industry can produce new drugs with high efficiency, high yield, low price and no bitterness, thus causing revolutionary changes in pharmaceutical industry. For hepatitis, cardiovascular diseases, tumors, AIDS and other major and difficult diseases for which there is no good medicine at present, people have high hopes for bioengineering and expect that genetic engineering technology can produce effective therapeutic drugs.
Fourth, the green revolution of crops.
Scientists have made great progress in using genetic engineering technology to improve crops. The breakthrough of genetic technology enables scientists to improve crops in ways that traditional breeding experts can't imagine. For example, genetic technology can make crops release pesticides themselves, plant crops in dry land or saline-alkali land, or produce more nutritious food. Scientists are still developing crops that can produce vaccines and foods that can prevent diseases. Gene technology has also greatly shortened the time for developing new crop varieties. It takes seven or eight years to cultivate a new plant variety by traditional breeding methods. Genetic engineering technology enables researchers to inject any gene into plants and cultivate a brand-new crop variety, and the time is shortened by half.
Fifth, DNA identification
DNA identification has brought a revolution to forensic science and criminal justice system. DNA has become the key evidence in countless trials, which helps the police and courts identify criminals in violent crimes with high credibility. You can determine the person who committed the crime, and you can also prove the innocence of the person who misjudged. Not only that, DNA identification can also be used to help find missing persons, victims of murder or accidents; It can also be used to prove or deny parent-child relationship.
Sixth, genetically modified animals.
With the rapid development of genetic engineering technology and its application in animals, the development of transgenic animals presents a "good situation". For example, gene breeding can provide "super animals" with high yield, high quality and disease resistance; Genetic engineering vaccine saves a lot of money for animal husbandry; Organ transplantation through transgenic animals.
The importance of the human genome
From the above facts, we can see that if we want to unlock the secrets of human beings, we must start by cracking the code of genes.
Understanding and controlling human genes will also play a powerful role in promoting the evolution of human species and the progress of human society. By exploring the known and unknown fields of human genes, we can find better genes that are more conducive to human progress, and human society will make an essential breakthrough.
Therefore, we can say that this costly and time-consuming human genome project is really necessary and will benefit forever. This may be a small step for biologists, but it is a very big step for human society.
Although the project has been announced to be completed, it has not yet produced a satisfactory human genome map, so scientists' exploration and research on the human genome are still in full swing. I hope that in the near future, human beings will be able to untie the veil of genes and understand that they control genes and bring infinite wealth to human society.
References:
1, Jaco's Human Gene Research Report, Chongqing Publishing House, 2006.
2. "What is life" edited by Qian, Kong Wei and Lu Dazhen * * * Central Party School Press, February 2000, p. 65438+.
3. C. Dennis, R. Gallagher and J. D. Watson preface The Human Genome Our DNA, Science Press, April 2003.
4. Journal of Practical Obstetrics and Gynecology 200 1 10,No. 17 (Journal of Practical Obstetrics and Gynecology 200 1/month,No. 17).
5. References:
Science (science)