SCIENTISTS fear men could be wiped out after discovering that endangered rats lack the male Y chromosome.
They say humans’ version of the gene data has been shrinking in size for years and may die out altogether.
Experts tested Ryukyu spiny rats living on the japonês island of Amami Oshima.
Only a few now remain — but none has the Y chromosome.
A baby’s gender is determined by chromosomes known as X and Y, which carry our DNA.
Males have XY while females have XX.
When conceiving a child, women contribute an X while men contribute the X or Y.
Study author Professor Asato Kuroiwa, of Hokkaido University, disse: “Y chromosomes in many mammals have been shrinking over tens of millions of years — and could eventually disappear.”
Award-winning geneticist Jenny Graves claimed two decades ago that our Y chromosome will eventually go.
Prof Graves, of La Trobe University, Melbourne, told New Scientist: “I think this latest piece of work is brilliant.
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The evidence is very compelling.
“There is no reason to think our Y chromosome is any more robust than the spiny rat’s.”
Prof Kuroiwa said: “I agree with Jenny. I also believe the Y chromosome will disappear.”