An old question has reignited the scientific and media communities recently.. "Is the Y chromosome, responsible for determining male sex, headed for extinction?"
This chromosome, which carries the secret of masculinity in humans, has lost 97% of its original components over 300 million years, leading some scientists to speculate that its role may end within a few million years, according to "ScienceAlert" science site.
However, evolutionary biologist Jenny Graves, whose initial calculations caused a "global uproar" two decades ago, confirmed that this does not mean the extinction of men as some media outlets have suggested, but just a possible evolutionary scenario. She said, "It amazes me that someone fears the extinction of men after 6 million years, while we as humans cannot guarantee survival for the next hundred years!"
Males without Chromosome Y
The evolutionary history of organisms has proven that losing the Y chromosome does not mean the end of males. This has indeed occurred in several species without affecting their reproduction, including Ellobius mole rats which live without any copy of chromosome Y after transferring its sex-determining genes to other chromosomes. The same happened with Tokudaia rats that replaced Y with a new evolutionary copy that efficiently performs the function of determining masculinity.
All these examples support the hypothesis that genes adapt and change their locations within the genome without collapsing the reproductive function.
Did the change begin without us realizing it?
In this context, Graves clarified that scientists may not easily discover the transfer of the sex-determining function to another gene because genetic studies are not typically conducted searching for "alternative sex". She continued saying, "There might be a human population that has developed a new gene that is more efficient... and it might have already happened without our noticing it."
Two different schools
Amid this ongoing debate, two scientific schools have emerged, the first being "Continuous Degradation" represented by Graves, which sees that the Y chromosome continues to shrink slowly, and that its replacement is just a matter of time, describing it as a "genetic waste dump" due to many ineffective duplicate copies in it.
Meanwhile, the second school, "Long-Term Stability", led by MIT, has been explained by researcher Jane Hughes that the Y chromosome has become stable today after a rapid loss period in the past, and it almost hasn’t lost any components in the last 25 million years.
Hughes also affirmed that "the remaining genes on Y are essential for the entire body, and natural selection would not allow their loss."
Yet, the disagreement between the two schools is not just theoretical debate, but reflects two differing views on the concept of evolution itself, posing a timeless question: "Is stability the rule... or is perpetual change the fate of genes?"
How did Chromosome Y shrink?
Regarding the scientific backgrounds of the debate, research indicated that chromosome Y was initially a duplicate of chromosome X, containing about 800 genes.
But as it began to perform the male-determining function, it lost the ability to exchange genes with X, which made it prone to gradual information loss over millions of years... and today only 3% of its original genes remain.
While this decline seems significant, scientists agree that gene loss did not occur at a steady rate, which makes any estimation of its extinction "just a broad guess."
And here Graves neatly summarized the situation, but at the same time, she has left millions of people in perpetual wonder, indicating that "the evolutionary history of chromosome Y may lead to its disappearance... or it may lead to its stability. The possibilities open from now and forever."
Yet in conclusion, everyone agrees that the future of men is not at risk, but the future of chromosome Y may change. Even if chromosome Y disappears one day, an alternative gene will emerge to take on the task – as has happened repeatedly in nature.
According to multiple research studies, masculinity is not dependent on a single chromosome but is an evolutionary process whereby genes can reorganize themselves remarkably.
