The Y chromosome, which determines the sex of human and other mammalian babies, is gradually degenerating. Scientists say that this chromosome may disappear in a few million years, and as a result, the human male race, and therefore humanity, may disappear. In addition, scientists underline that we need to develop a new sex gene.How does the Y chromosome determine human sex?
In humans, as in other mammals, females have two X chromosomes, while males have an X and a smaller Y chromosome. The X chromosome contains about 900 genes unrelated to sex, while the Y contains about 55 genes and a large number of non-coding DNA.
Although the Y chromosome carries fewer genes, it has a serious feature. The Y chromosome, around the 12th week of pregnancy, activates its other sex-determining genes and produces hormones that make the baby a boy. In 1990, this main gene was named SRY. This gene triggered another gene called SOX9, enabling the embryo to develop into a male.Y chromosome is lost
Jenny Graves, Professor of Genetics from La Trobe University in Australia, is one of the scientists who revealed that humans will lose their Y chromosome. “So, if someone visits Earth 11 million years from now, they may not find any humans,” Graves wrote in The Conversation. Or he may encounter several different types of people kept apart by different gender determination systems.”
Behind this discourse lies the result of studies on mammals. “The mole rats of Eastern Europe and the spiny rats of Japan have some species in which the Y chromosome and SRY are completely lost, Graves said. In these species, the X chromosome remains single or double (XX or just X) in both sexes. It is unknown how these species determine sexes.”On the other hand, a team led by Hokkaido University biologist Asato Kuroiwa discovered that most of the genes on the spiny mice Y chromosome had been moved to other chromosomes, but found no trace of either SRY or its replacement gene.
In the latest study of Kuroiwa and his team, gene sequences that are not found in female chromosomes but only seen in males’ chromosomes were detected. It is stated that these genes may be the genes that determine the sex.
Graves states that the human Y chromosome, which started to disappear as a result of all this, may gain a similar ability in the future. Graves also said, “…However, the evolution of a new sex-determining gene comes with risks. What if more than one new system develops in different parts of the world?” used expressions.
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