Dragaera

Dzur and Sex

Tue Jan 27 13:10:10 PST 2004


On Tue, 27 Jan 2004, Damien Sullivan wrote:

> On Mon, Jan 26, 2004 at 07:06:59PM -0800, Philip Hart wrote:
>
> > > I think sperm in general are parasite gametes in the sexual process;
> > > some thought is that the original sexual gametes would have been 'fair',
> > > or equal in size, but it makes sense for one half to cheat and make lots
> > > of smaller gametes and off the race goes.  The same logic should
> > > probably apply to actual males, except when offset by
> > > competition-for-mating issues, which turns out to be pretty often.
> >
> > The argument in Matt Ridley's _The Red Queen_ has it that sperm are small
> > because of selfish gene effects between the X and Y chromosome and the
> > female mitochondria genes fighting for dominance or something - and maybe
> > something having to do with parasitism.  Maybe time for a reread.
>
> I should be clear: I didn't mean that sperm came from some external
> parasite, just that they're being selfish, putting most of the work of
> reproduction onto the egg.

Ok, if anyone cares about this they can check out the chapter "Genetic
Mutiny and Gender" in Ridley's _The Red Queen_, which is where I got the
latter two points (the first being either pararectal or related to the 2nd
point) - sperm have their organelles stripped (so they don't fight with
the egg organelles) and their cytoplasm siphoned off (in order to get rid
of cellular parasites).  He's a really excellent (if a tad political)
science writer I recommend to everybody.  Dawkins's _The Selfish Gene_
touches on these points but I find it a lot harder to follow.

Sperm competition is also important (depending on the species).  Ridley
says we make "kamikaze sperm" which may act to impede rivals' sperm...