20 13 On April 2nd, one of Australia's most famous female scientists, Jenny Graves, a professor at the Applied Ecology Association of the University of Canberra, gave a speech at the Australian Academy of Sciences and made a shocking prediction on the future of human males.
Professor Graves said that the male sex chromosome is XY, and because the sex chromosome has only one Y chromosome, it is becoming more and more difficult to repair its own "defects", and the Y chromosome has evolved for at least tens of millions of years and contains no more than 100 genes. On the contrary, female sex chromosome XX is composed of a pair of X, which enables X chromosome to repair its own defects through another "twin". Up to now, X chromosome still contains about 65,438+0,000 healthy genes. Professor Graves predicted that the inherent "fragility" of male Y chromosome means that men are gradually going extinct, and the time limit for male extinction on the earth is about 5 million years! Professor Graves's prediction of "male extinction" has caused fierce controversy in the scientific community. Many other scientists advise men not to be too alarmed, because 5 million years is a long time, and the development of medical science may solve the problem that Y chromosome is difficult to repair its own defects. Or, when the Y chromosome is extinct, another chromosome may take over the function of the Y chromosome, thus creating a brand-new male race to continue to multiply on the earth.
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The "girl country" is not necessarily a myth.
Although there are stories of "girl country" in both Chinese and western myths, what would it be like if there were no men in a world? In fact, according to the prediction of Jenny Graves, an Australian female scientist and a professor at the University of Canberra, the "girl country" is not necessarily a myth, but it may become a reality on the earth five million years later! At the beginning of April, Professor Graves made a sensational prediction in a speech delivered by the Australian Academy of Sciences: due to the inherent fragility of male Y chromosome, men on the earth will be completely extinct in 5 million years! By then, there may be only all women left on the earth, and it has become an out-and-out "daughter country"!
Professor Graves, 72, is one of the most famous female biologists in Australia. As early as 197 1, she got her doctorate for her research on DNA. Professor Graves' research fields include the function and evolution of mammalian sex chromosomes, sex control genes and so on. She became a member of the Australian Academy of Sciences on 1999. Professor Graves, 72, is an authoritative figure in the field of sex gene research in Australia!
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Y chromosome is difficult to repair its own "genetic defect"
As we all know, the sex of men and women is determined by the sex chromosomes in 23 pairs of human chromosomes. The sex chromosome pair of male individual cells is XY, and the sex chromosome pair of female cells is XX.
Professor Graves claims that women's sex is determined by two X chromosomes, but there is only one Y chromosome that determines men's sex, which leads to the increasingly unfavorable dilemma of Y chromosome in evolution. Professor Graves said that at the beginning of evolution, both the Y chromosome and the X chromosome had the same number of genes. However, after tens of millions and hundreds of millions of years of evolution, there are only 100 genes left on the Y chromosome of modern men, including SRY gene, which is the "male control switch" gene that determines whether the embryo is male or female. On the contrary, however, women have a pair of X chromosomes on their sex chromosomes, which still contain about 1000 healthy genes. The "decline" phenomenon of Y chromosome on the evolutionary path has been quite obvious.
Professor Graves explained that the reason why the male Y chromosome gradually "declines" is that women have two X chromosomes, while men have one X chromosome and one Y chromosome respectively. Y chromosome, which determines male sex, belongs to the "loner" in male sex chromosome, and it is increasingly difficult to repair the "defect" caused by cell division by its own error correction function.
Women are different. Because women have a pair of X chromosomes, even if one of them has a genetic defect, they can "repair" themselves through the other healthy twin X chromosome. Y chromosome is very active in the testis produced by male sperm. Professor Graves called it a "very dangerous place" because there are many cell divisions, and each division may produce genetic variation or gene loss. Because of the inherent loneliness and fragility of Y chromosome, it is increasingly difficult to repair the genetic defects caused by cell division, which means that men will gradually become extinct in the course of human evolution.
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Most of the remaining genes on the Y chromosome are "junk genes"
Professor Graves said: "In male sex chromosome pairs, there is only one X chromosome; However, in the female sex chromosome pair, there are two X chromosomes, just like a pair of friends. When one X chromosome is defective, it can repair its own defect by exchanging data with another X chromosome. However, if the Y chromosome encounters a genetic defect, it is obviously impossible to repair itself in this way, and it can only face a downward spiral. "
Professor Graves told the audience in his speech: "This is really bad news for all the people present." However, the bad news doesn't stop there. Professor Graves said that even if there are less than 100 genes left in the male Y chromosome, most of them are "junk genes". Professor Graves said: "This is a remarkable example of what I call' stupid design', which is an evolutionary accident."
Professor Graves finally predicted that the male Y chromosome will disappear completely after 5 million years, which means that men who depend on the Y chromosome to determine their sex will also be extinct from the earth with the Y chromosome after 5 million years.
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Other scientists
Men are advised not to panic.
Professor Graves's amazing prediction of "male extinction" has caused fierce controversy in the world scientific community. Because Professor Graves is a respected professor of biology and an authority in the field of sex gene research, her prediction obviously has considerable weight and credibility. But there are also many other scientists who advise men not to be too alarmed, because 5 million years is a long time, and the rapid development of science may successfully solve the problem that Y chromosome is difficult to repair its own defects before male extinction; Secondly, when the Y chromosome is extinct, another chromosome may take over the function of the Y chromosome, thus creating a new kind of male to continue to reproduce on the earth.
Professor Robin Ravel-Baiji, a sex chromosome expert at the National Institute of Medicine in London, said: "In the past at least 25 million years, the Y chromosome has not lost any genes, so I don't think men have anything to worry about at all." Chris Mason, a professor at University College London, said: "For medical science, scientists will have a lot of time to study and solve the self-repair problem of Y chromosome in five or six million years, and this research result may even win the Nobel Prize."
Professor Graves put forward another possibility. He said that when the Y chromosome disappears, another chromosome is likely to take over the function of the disappeared Y chromosome, thus creating a completely new male species. In fact, there are precedents for this phenomenon in nature. For example, Japanese hamsters can still survive and reproduce after losing the Y chromosome. According to Professor Graves, she thinks this evolutionary process may have been carried out in some isolated human races.