1902, Sutton and Boveri found that the process that Mendel said genetic factors were passed from parents to offspring was parallel to the process that chromosomes in cells were passed from parents to offspring, so they thought that genetic factors were on chromosomes. 1909, Dutch geneticist Johnson put forward the term "gene" which is well known to modern people, replacing the concept of "genetic factor". Since then, American scientist Morgan and his colleagues have irrefutably proved that genes are on chromosomes with fruit fly experiments, and put forward the law of chain exchange in classical genetics.
Genes are on chromosomes, which are composed of protein and nucleic acids. So who is the genetic material? The development of biochemistry and biophysics shows that nucleic acid is a real genetic material.
1953 In April, the British magazine Nature published an epoch-making paper by Watson and Crick: Molecular Structure of Nucleic Acid. In this paper, they published the double helix structure model of deoxyribonucleic acid (DNA) molecule. The publication of this model immediately shocked the world. The biochemist Pauling wrote: "I believe that this discovery of DNA double helix and the progress it will make will surely become the greatest progress in life science and all our understanding of life in the past 100 years."
After discovering the double helix structure of DNA molecules, Watson and Crick put forward a semi-conservative replication model of DNA molecules, which successfully revealed the genetic mechanism of "as you sow, so you reap" at the molecular level.
At the end of 1950s, the concept of triplet genetic code was put forward, and the work of deciphering genetic code began. In the 1960s, all 64 genetic codes were cracked.
Now we know that genes are DNA fragments with genetic functions on chromosomes, and the number of chromosomes in each organism is limited. For example, we humans have 23 pairs of 46 chromosomes from our parents. Therefore, if we measure the DNA sequences on all 23 pairs of chromosomes, we may know almost all the genetic secrets of human beings.
In order to speed up the understanding of life and better serve human health care, scientists decided to systematically interpret genes in a short time, that is, to finally clarify the arrangement order of all genetic information stored in the genome, which is the Human Genome Project.
This topic was first put forward by studying the genetic effects of radiation. Especially after the atomic bombings in Nagasaki and Hiroshima, Japan, when studying the gene mutation rate of the descendants of survivors, it was found to be almost the same as that of the normal population. However, there should be obvious differences between these two groups in theory. The first possibility is that the existing detection methods are not sensitive enough to reveal its true meaning. In order to accurately detect the human mutation effect caused by this radiation, the best method is to determine the human genome sequence and compare the gene sequences of normal people and irradiated people. Later, some scientists in the United States suggested that in order to understand the formation mechanism of tumors, it is best to compare the genomes of tumor patients with those of normal people and find out the differences. This idea was first put forward by American biologist and Nobel Prize winner Durbeck. 1On March 7th, 986, he published an article entitled "The Turning Point of Cancer Research-Complete Analysis of the Human Genome" in the American journal Science, pointing out that the occurrence of human diseases, including cancer, is directly or indirectly related to genes, hoping that people will study the whole human genome from a global perspective, instead of studying a certain gene they are interested in. This motion led to a series of activities to formulate a research plan for the human genome.
It was not the medical research department that started the large-scale genome project first, but the US Department of Energy. At the seminar attended by well-known biologists such as Watson, one of the discoverers of DNA double helix structure, some people agreed that some young scientists lacked enthusiasm. They worry that this expensive project will weaken the country's high-quality biomedical research projects. Watson, on the other hand, is worried that the leaders of the Department of Energy are all physicists, and it is difficult for biology to lead the way. Therefore, he believes that it is safer to invite the National Institute of Medical Sciences (NIH) to participate in the project, and Congress should allocate special funds as financial support. After several years of coordination and efforts, NIH established the Human Genome Research Center on 1989, with Watson as the first director. 1990, the US Congress approved the "Human Genome Project" and officially launched it on 10+0.
The goal of the Human Genome Project is to analyze all the DNA sequences of the human genome in 1990, and it will cost 3 billion dollars in 15. (1998, the original plan was revised, and the sequencing was announced to be completed in 2003 two years in advance. On May 10, 2000, the "sequence diagram" was completed two years earlier, that is, on June 5438+0, 2006. In fact, on June 25th, 2000, the draft of human genome work was completed. Its main contents include: gene map and sequence analysis of human genome; Identification of human genes; Establish genome research technology; Genome analysis of model organisms in human genome research, such as yeast genome analysis.