A recent study from the Whitehead Institute indicates that the male Y chromosome is unlikely to disappear, as was previously thought.
The Wellcome Trust / REUTERS
Contrary to previous belief, men may not be on the way out after all. New research reveals that the Y chromosome is not rapidly degrading and is unlikely to disappear.
The idea that the male sex chromosome and its owners would someday vanish is based on the process by which our cells form sperm and eggs. These cells each contain pairs of chromosomes, or packets of DNA. When these cells divide, their chromosome pairs swap genetic information in a process called recombination (like shuffling two decks of cards before dividing them back into two decks).
Recombination allows the cells to repair genetic mistakes and mix and match genes. But unlike the other 45 chromosomes that carry human genetic information, the male sex chromosome, the Y, does not come with a matched partner to recombine with. Instead, it gets paired with an X chromosome. That means that when it comes time for cells to divide, the Y has no one to recombine with.
"The Y never gets a chance, because there are never two Ys in a cell," said study researcher Jennifer Hughes, Whitehead Institute in Cambridge, Mass. "What we have shown time and time again is that if you don't recombine, you degenerate."
This trick of nature means that today's Y chromosome contains only 3 percent of the genes it had when it started evolving separately from the X chromosome 200 million to 300 million years ago. That finding led to speculation that the male chromosome could crumble completely within hundreds of thousands or millions of years, perhaps taking men as we know them with it.