[Q] You were pointing out the sporadic distribution of asexual reproduction in the taxonomic tree, and you said, 'Wouldn't it be nice if we could find something else that had the same kind of sporadic distribution,' but you never actually said whether you'd found any such examples.

Well, I've not done the serious statistics. I mean, nowadays, you know one has to do proper statistics before you would justify a statement of that kind. But I have a candidate which I would like somebody to do the statistics on, and it's rather an unexpected one. It's the habit of producing your young alive, viviparity. Now, you think, come on, that can't be right, all mammals are viviparous, you know, one big taxonomic group. I think the fact that mammals are all viviparous is a little like the Bdelloid rotifers all being parthenogens. It's... it's a curious quirk. By and large, viviparity crops up, particularly in the vertebrates, in a very irregular way.

[Q] It's very sporadic in teleost fish.

That's right. I would like to see somebody do a serious statistical survey of the distribution of viviparity in the vertebrates. And I think they might find that mammals are really weird, in being... clearly mammals, it's an invention that's succeeded.

[Q] It's just one datum.

It's one datum in the statistics. I think someone, you know, your colleague, Paul Harvey, or one of his students, should have a serious go at it. Maybe there are others, I've not got a good example.

[Q] But in order for the analogy with asexuality to be correct, it would have to be the case that... I mean you would have to be predicting that viviparity, when it arises, quickly drives the species extinct, wouldn't you?

That's right, yes.

[Q] Is that what you want to say?

If that's what the data says, that's what I want to say, yes, I think it's a terrible mistake. 

[Q] There are other things, like halpo-diploidy, which have the opposite kind of distribution, which are not sporadic, which really do characterise major taxa.

Yes, again, when I originally put forward the argument that the taxonomic distribution of parthenogenesis was... was patchy, I did use the haplo-diploids as a counter example to show that other breeding systems could, if they arose, spread to whole groups, and it... you didn't very often get this occasional example. But I'm afraid I didn't do the statistics properly, I mean, somebody should. In those days, you see, you could make these kind of statements without doing the statistics. Nowadays, the whole thing has... the rules of the game have changed and you have to do it properly, I'm afraid.