The extinction rate of the Y chromosome is greatly exaggerated

[Детективное агентство ИКС-Инфо.]

The rate of extinction of the Y chromosome is greatly exaggerated - the male sex chromosome of primates has lost only one gene over the past 25 million years.

The history of the Y chromosome began 200-300 million years ago; It is believed that it first appeared in the common ancestor of all mammals. Of course, living organisms and before that were divided by sex, but before such a division, according to scientists, was determined by environmental factors. Now gender has received a hard genetic definition. The SRY gene has split off from the SOX3 gene. The chromosome that received the SRY gene became male, the chromosome with the SOX3 gene became female.
Like all ordinary paired chromosomes, X and Y initially exchanged similar sites during the recombination process. But gradually, the male chromosome was losing DNA fragments, and it still had fewer genes suitable for exchange with the X chromosome. Now our sex chromosomes can exchange only material from small terminal sections. In 2002, an article appeared in the journal Nature, in which a group of Australian scientists predicted the male chromosome to die soon - for about 10 million years (not such a long time on an evolutionary scale). It should be clarified that this does not necessarily mean the disappearance of the male sex itself: in some mammals (for example, mole rats and bristled rats) with the missing Y chromosome, the genes of the sex are distributed over other chromosomes.
The death of the Y chromosome was heatedly discussed by the scientific community until a group of geneticists from the Whitehead Institute (USA) compared the sex chromosomes of humans, chimpanzees, and rhesus monkeys. Chimpanzees separated from their common ancestor about 6 million years ago, and during this time their Y chromosome lost a large number of different genes. But one group of genes not only remained, but also increased due to copies. These are genes responsible for sperm production. Such a specialization of the sex chromosome, according to scientists, is important for those species whose males practice promiscuous sex. In this case, only one thing is required from the Y chromosome - as many sperm cells as possible, and whether she can do anything else is completely unimportant.
To more closely trace the history of the male chromosome in primates, the researchers checked the sequence of the Y chromosome in rhesus monkeys. These monkeys went on their evolutionary path even earlier than chimpanzees - 25 million years ago. Scientists compared the chromosomes of macaques and humans. It should be noted here that for all the difference between the Y chromosomes of the two species, they code for the most part the same genes. Researchers expected macaques to have even more copies of “sperm” genes and fewer general purpose genes due to a longer period of independent evolution. But then scientists made an unusual discovery: it turned out that the difference between the Y chromosomes of humans and rhesus monkeys is in one gene. That is, in the 25 million years of our separate evolution with macaques, the human Y chromosome has lost a single gene.
Scientists publish the results of research in the journal Nature.
Once upon a time, the male sex chromosome may have been rapidly losing genes, but by the time primates appeared on Earth, its extinction rate had slowed significantly. In general, according to scientists, we can safely expect that even after 50 million years, human men will be with their Y-chromosome. Unless, of course, our species itself disappears due to its own activity. In this regard, the authors of the work somewhat maliciously suggest that their colleagues pay attention to more pressing problems like global warming, rather than worry about the fate of the Y chromosome.

[DLMURL] https://science.compulenta.ru/663199/ [/ DLMURL]

 

[Матушкин Андрей Николаевич]

Thanks for working on the forum.