Nick Lane

Yeah.

So males do not pass on their mitochondria.

And then this is beginning to explain, you know, differences in multicellular organisms between the sexes, between the nature of the germline.

So in some sense, male men do not really have a germline in the sense that women have a germline.

So in the female germline, you make these oocytes and you put them on ice effectively.

You look after them.

You switch them off as much as you can.

You try and protect them from mutations.

You mollycoddle them effectively, whereas men just mass produce sperm full of mutations.

I mean, there's a lovely phrase from James Crow, who's a geneticist, who said there's no greater genetic health hazard in the population than fertile old men.

Yeah.

So why would you go on mass-producing sperm all the time?

Well, part of it is you don't have to pass on the mitochondria.

So you're freeing yourself up to mass-produce sperm, and then you've got the same things out.

Some of them are full of mutations, but a lot of them aren't.

You mass-produce them, and the chances are it's going to work out okay.

Because the ones that can swim best, for example, are the ones that are more likely to.

That's not strictly true, but you can imagine it along those lines.

But in the case of oocytes, in the case of the egg cells, you're passing on those mitochondria.

You don't want to be accumulating mutations in that mitochondrial DNA.