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John Reed johnreed at stein1.u.washington.edu
Wed Oct 6 18:29:58 EST 1993

In article <loats1.749942282 at husc9>,
James Loats <loats1 at husc9.harvard.edu> wrote:
>>I am interest in knowing whether parthanogenesis has evolved in the male 
>>sex of any species.  I would presume not, for evolutionary reasons, but I 
>>would like to know for sure.  I would also like to know other peoples 
>>opinions as to why this has not occured.  
>Well, my own opinion as to why this has/would not occur is more for
>physiological than "evolutionary" reasons:  males don't do parthenogenesis
>because if they did, they'd be called females.  My understanding is that
>"male" and "female" are defined in general by the relative motility of
>their gametes (i.e. "sperm/pollen" are motile, "eggs/ova" are not), and
>consequently, in those species which "give birth", by who bears the young
>or lays the egg.

Why couldn't a motile gamete parthenogeneses (as you say, verb form?).  
The reason I presumed it never occured was that motile gametes don't have 
the surrounding tissues (placenta, endosperm) for the developing emryo, 
whether it is derived from parthogenesis or fertilization.  I still don't 
see any real reason you COULDN'T have parthenogenesis in males, just a 
good explanation for why it is at least less common.  So far I haven't 
got any replies indicating that it does occur in ANY male of ANY species 
on Earth.

>Jim Loats                   * "I pass the test.  I shall diminish,
>loats1 at husc.harvard.edu     *  and go into the West, and remain
>Bacterial Motor Works--the  *  Galadriel."
>Ultimate Swimming Machine!  *             -- J.R.R. Tolkien

John Reed
College of Forest Resources, AR-10
University of Washington
Seattle, WA 98195
Internet: johnreed at u.washington.edu

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