The Y chromosome carries a gene called SRY, which turns on male genes on other chromosomes.
The Amami spiny rat, one of the species that lack a Y chromosome and the Sry.
As per the press release, under normal conditions, the Sry gene on the Y chromosome triggers the formation of the testes. However, the Sry gene, along with the Y chromosome, has vanished in a small number of rodent species.
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