MEN are on the road to extinction as their genes shrink and slowly fade away, according to one expert.
Professor Jennifer Graves, a leading researcher in human sex chromosomes, said the male Y chromosome was dying and could run out within the next five million years.
But she said men may follow the path of a type of rodent that manages to reproduce
despite not having the vital genes that make up the Y chromosome.
She told medical students at the annual outreach public lecture at the Royal College of Surgeons in Ireland that a second species of human beings could even be born in the future.
"You need a Y chromosome to be male," said Prof Graves, from Australia.
"Three hundred million years ago, the Y chromosome had about 1,400 genes on it, and now it's only got 45 left, so, at this rate, we're going to run out of genes on the Y chromosome in about five million years. The Y chromosome is dying and the big question is what happens then."
The male Y chromosome has a gene – SRY – that switches on the development of testes and pumps out male hormones that determine maleness.
She said it was not known what would happen once the Y chromosome disappeared. "Humans can't become parthenogenetic, like some lizards, because several vital genes must come from the male," she said. "But the good news is certain rodent species – the mole voles of Eastern Europe and the country rats of Japan – have no Y chromosome and no SRY gene.
"Yet there are still plenty of healthy male mole voles and country rats running around. Some other gene must have taken over the job and we'd like to know what that gene is."
Prof Graves' work has paved the way for developments in the diagnosis of gender disorders and gender-related disease in humans.
