Are Men Eventually Going to Disappear? Male-Determining Y Chromosome Gradually Shrinking Over Time

The X has around 1,000 genes whereas Y has only 45, and the study suggests that the Y chromosome is slowly shrinking even further

The Y chromosome might be dying out, prompting discussions about the issue that men can disappear with it. A person's sex gets determined by whether they have X chromosomes, which causes ovaries to develop, or an X and a Y that causes the development of testes.

Among the two, the X has around 1,000 genes whereas Y has only 45, and research suggests that the Y chromosome is slowly shrinking even further. The genes develop mutation with time, few of which are harmful. The chromosomes can avoid passing on such deadly mutations by mixing and matching with each other while meiosis takes place during which our forming bodies develop sperm or eggs.

The process breaks up the genes and also makes sure that only the harmless and strong ones get passed on. Only the X chromosomes can exchange with each other while the Y is not that much similar for combining.

Are Men Doomed?

Representational Picture Wikimedia Commons

As people do not generally have two Y chromosomes, it cannot recombine with itself and thus it has turned out to be smaller over the millions of years of evolution. The study conducted by Jennifer Graves, who is a geneticist at La Trobe University in Melbourne, suggested that 166 million years ago the Y chromosome had a similar number of genes as X.

"So it doesn't take a great brain to realize that if the rate of loss is uniform —10 genes per million years — and we've only got 45 left, the whole Y will disappear in 4.5 million years," she told Live Science.

The study suggested that the rate of the degradation has decreased and that the human Y chromosome has lost just one gene after humans and rhesus monkeys diverged 25 million years ago. But the loss of the Y chromosome totally is still a probability, as it took place to other species that include underground rodents called the mole voles, as well as certain species of the spiny rats in Japan.

This does not mean that men are doomed, as the loss of the Y chromosome does not omit the male sex from a species as both the spiny rats and mole voles still have both the genders. "People think that sex is sort of a very determined thing," Rasmus Nielsen, a geneticist at the University of California, Berkeley stated. "That if you have a Y chromosome, then you're a man, or you don't have [a] Y chromosome, then you're female. But it doesn't work like that," the geneticist added.

However, 95 percent of the genes that are expressed differently between the males and females do not actually live on X and Y chromosomes. "Losing the Y chromosome doesn't mean losing the male," Nielsen said.