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Re: Parthenogenesis in vertebrates



--- "T. Michael Keesey" <keesey@gmail.com> wrote:

> On 5/23/07, Jura <pristichampsus@yahoo.com> wrote:
> >
> > Turkeys can. There are probably a few other birds
> too,
> 
> Interesting.

+++++++++++++++++++++++++++++++

It seems to be possible for chickens too. It might be
true for other galliformes too.

_________________________________


> > > Is it males being heterozygous that prevents
> mammals
> > > from reproducing parthenogenetically?
> >
> > I don't see why. Heterozygosity is well
> represented
> > among squamates and birds too, and it doesn't stop
> > them from being parthenogenic.
> 
> Yes, but it's the females who are heterozygous in
> those groups, no? Or
> is the matter (need I eve ask?) more complicated
> than that?
> 
> -- 
> Mike Keesey

++++++++++++++++++++++++++++++++++++++++++++++

Having males be the homozygous sex in reptiles has the
advantage of allowing the species to return to sexual
reproduction very quickly (since all parthenogens
would be homozygous). That's about it, though. 

I was just pointing out that having all the offspring
be female isn't really a substantial enough pressure
to eliminate this trait in mammals. As I stated in the
previous post, there are certain lizard species that
actually evolved a way around the production of male
offspring so as to produce a completely female
population. 

While searching for other parthenogenic bird species,
I came across this article on the BBC from 2004. 

http://news.bbc.co.uk/2/hi/science/nature/3643847.stm


Apparently the problem with mammals is genetic
imprinting of certain regulatory sequences.

Man, mammals are so weird. >:)

Jason

"I am impressed by the fact that we know less about many modern [reptile] types 
than we do of many fossil groups." - Alfred S. Romer


       
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