Y Chromosome Fading Away: Could Men Become Extinct? -

The Y chromosome, responsible for determining male sex, has been slowly degenerating over millions of years and may eventually vanish. But does this mean that men will also disappear?

Survival Without the Y Chromosome

Interestingly, the extinction of men may not be inevitable. Scientists have observed that certain rodent species have continued to thrive despite losing their Y chromosomes. A 2022 study published in the Proceedings of the National Academy of Sciences highlighted how the spiny rat evolved a new male-determining gene, suggesting that a similar process could occur in humans.

The Evolution of a New Sex Gene

Researchers now believe that the emergence of a new sex-determining gene could prevent the extinction of men. This finding gives hope that even if the Y chromosome vanishes, men could continue to exist through evolutionary adaptations.

The Decline of the Y Chromosome

The Y chromosome began to deteriorate around 180 million years ago when a segment broke off and reattached in a reversed orientation. This event hindered the Y chromosome’s ability to recombine with the X chromosome, leading to the accumulation of harmful mutations. Over time, this process caused the Y chromosome to lose 97% of its ancestral genes.

X vs. Y: The Gene Comparison

While the Y chromosome has dwindled to just 55 genes, its counterpart, the X chromosome, has retained around 900 genes. Despite having fewer genes, the Y chromosome remains crucial because it carries the SRY gene, which triggers male development in embryos.

The Unique Role of the Y Chromosome

In mammals and humans, females have two X chromosomes, while males possess one X and one Y chromosome. The Y chromosome is essential for initiating the development of male characteristics by acting as a switch to start the formation of testes during embryonic development.

As evolutionary biologist Melissa Wilson from Arizona State University noted in a 2014 paper, “Our sex chromosomes weren’t always X and Y.” This historical perspective adds context to the ongoing changes in the Y chromosome and its future implications.