Dr Ann Jones

This type of turn to parthenogenesis is often framed as a last resort for the female.

That she must be under extreme stress when no male has ever been present, when she has no other option.

It's been called a Hail Mary.

I knew that extraordinary birth narrative trope would turn up again.

But Leonie the shark's case is quite novel because she had previously had babies the boring, normal, vanilla way with old Leo, and she switched reproductive modes after their breakup.

She could have retired, but instead,

She pulled out this miracle.

So Christine took this as a hint of what to research next.

How much is parthenogenesis happening even when there is access to males?

Oh!

So virgin births in sharks and rays might be way more common than we ever suspected before, but largely invisible without genetic testing.

How much more is there out there?

In Californian condors, a bird that almost went extinct, and actually that's why they've got heaps of genetic info on each individual, they recently found that two females had reproduced parthenogenically.

Without genetic tests, we'd perhaps never have known this.

You might notice that we haven't talked about any examples of parthenogenesis in mammals, apart from Jesus and other historical and mythological creatures.

Most of this virgin birth stuff that happens on Earth is in plants and invertebrates, really.

And on top of that, parthenogenesis has been observed in 80 taxa of vertebrates across fish, reptiles and amphibians.

But we have much less evidence, almost none, for this happening in mammals.

This is because apparently there's certain genetic passcodes for mammals that must come from two parents.

It's called genomic imprinting and it sort of makes the puzzle pieces come together.