FEMALE OF THE SPECIES

A self-replicating sisterhood of salamander gene thieves

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THERE'S A PECULIAR posse of amphibians creeping through the damp leaf litter of the North American Great Lakes. They're about the size of a slim sausage, splotchy brown with watery smiles and bulging eyes. Cute, maybe - but, biologically, they are rewriting the rules of sex.

Meet the unisexual mole salamanders, an all-female lineage that's been thriving for millions of years by not just cloning but occasionally stealing DNA from other mole salamander species. They are the only known vertebrate to reproduce via a process called kleptogenesis.

If that sounds like the reproductive equivalent of a Netflix heist drama, you’re not far off. These self-replicating sisters are members of a group that also includes five sexually reproducing mole salamander species.

The unisexual sisterhood evolved from a hybridisation event, more than five million years ago, between these sexually reproducing species. Now the unisexuals parasitise their sexually reproducing cousins' sperm for their own purposes.