Will Men Be Wiped Out By A Fading Y Chromosome? What Current Science Reveals

A recent study suggests a surprising future for human reproduction: the Y chromosome, which is crucial for determining male sex, is gradually shrinking and might eventually disappear. This could result in a world where only girls are born.

One may think about the possible implications of this genetic-level change that researchers are now pursuing: whether it would allow a new sex-determining gene to evolve or whether other mechanisms of reproduction might develop. By disappearing, the Y chromosome would alter the face of human populations' reproduction and raise questions pertaining to the long-term survival of our species.

The 2-year-old research paper that was published in Proceedings of the National Academy of Science shows how the spiny rat has evolved a new male-determining gene.

The scientists working on this subject have confirmed that the Y chromosome, crucial for male development, is shrinking and could eventually disappear. This theory, not from sci-fi, suggests a future where only females are born. While men's XY chromosomes trigger male development, the Y chromosome's current size and decline raise concerns about potential new human species.

One of them, Professor Jenny Graves, explained this concept through the lens of the platypus.

'In platypus, the XY pair is just an ordinary chromosome with two equal members,' she said, writing for The Conversation. 'This suggests the mammal X and Y were an ordinary pair of chromosomes not that long ago.

'In turn, this must mean the Y chromosome has lost 900 to 55 active genes over the 166 million years that humans and platypus have been evolving separately. That's a loss of about five genes per million years. At this rate, the last 55 genes will be gone in 11 million years.'

Could Men Eventually Disappear from Earth?

"The finding supports an alternative possibility-that humans can evolve a new sex-determining gene," said Professor Graves.

"But it may still not be that simple. 'Evolution of a new sex-determining gene comes with risks,' she said. 'What if more than one new system evolves in different parts of the world?

A "war" of the sex genes could lead to the separation of new species, which is exactly what has happened with mole voles and spiny rats.

So, if someone visited Earth in 11 million years, they might find no humans-or several different human species-kept apart by their different sex determination systems.