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Genome Number "China Volume" of Human Genome Program Fixed
Professor Yang Huanming, person in charge of liaison affairs of Human Genome Program (China), Thursday said during an exclusive interview that with the completion of the "China Volume" of Human Genome Program, the gene number in this field has finally come to light. Chinese scientists have identified 122 genes, 36 of which are the newly discovered ones.
��The density of genes in this field is quite identical with the general density of human genome," Yang said, "the clear definition of the accurate number and position of the genes has laid a solid foundation for the further study on genetic functions."
Genes in chromosome are a small part of DNA that determines development of human being's hereditary qualities. Genes not only can transmit the hereditary information to the next generation by way of reproduction, but can also make the information expressed. On February 15th Scientists from six countries who participated in the Program jointly declared the preliminary achievements of the study on human genome. One of the items aroused broad interests of the public and the media: human beings have only about 30,000 genes instead of the 80,000 to 100,000 genes as assumed in the past.
China, as an only developing country participating in the Human Genome Program, was assigned sequencing task of 30m base pairs of No 3 chromosome. After a large scale of sequencing work, recently we've seen Chinese scientists finalized the map of "China Volume" on the basis of the "working frame" mapped out last year, a task finished two years ahead of the schedule. Scientists identified altogether 122 genes in the "China volume". Among the 86 known genes, functions of 55 genes have been decided. Eight of them are directly related to the diseases such as cell carcinoma of kidney, MD (muscular dystrophy), anemia, etc.
Besides, scientists have also found out in 31 genes 75 different ways of cutting. One of the genes can produce more than eight proteins of different structures. It is the one with the most numerous cutting ways that has ever been discovered up till now.
Experts pointed out that the different cutting ways decide that one gene produce more than one protein. That is perhaps where lies the reason why human beings have only about 30,000 genes yet their life mysteries turn out to be so complicated.
��Human being has about 30,000 genes, however, the number of proteins may reach several hundred thousand or even several million. It indicates that, comparing with the original assumption of "one gene codes one kind of protein", but now each gene may produce diversified proteins," said Wang Jian, acting director of Genome Information Center of Chinese Academy of Science.
Sources say that Chinese scientists have discovered that the size of these genes is quite different from each other. The largest one has about 880,000 alkali-bases. Its genetic structure has hitherto remained unknown. Between the two smallest genes, one "in charge of" coding has 21 amino-acidic polypeptide, the other "in charge of" coding has 110 amino-acidic protein related to nasopharyngeal carcinoma.
Since September 1999, China has shouldered the 1-percent genome sequencing work of the human beings. In spite of a late start, Chinese scientists, supported by the state, have overcome various difficulties and completed the sequencing-map two years ahead of the schedule, reading out the "China volume" of the Program.
By PD Online staff member Du Minghua
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