In article <schwarze.ccomail-2909950037410001 at 22.214.171.124> schwarze.ccomail at starbase1.caltech.edu (Erich Schwarz) writes:
>From: schwarze.ccomail at starbase1.caltech.edu (Erich Schwarz)
>Subject: Re: man-ape hybrid
>Date: Fri, 29 Sep 1995 00:37:40 -0800
>Ed Heist wrote:
>> ... intergeneric hybrids among
>> vertebrates are rare, and that I am aware of studies in which attempts
>> to produce intergeneric hybrids in vertebrates resulted in successful
>> fertilization but abnormal development and death of the embryos, just
>> the phenomenon described in the original post of this thread.
> Humans and chimpanzees are probably about 6 million years apart. How
>chronologically separate are horses and donkeys, or lions and tigers, both
>of which can produce viable hybrid offspring?
The idea that there could be a difference between say, interspecific (but
congeneric) hybrids and intergeneric, interfamilial etc. hybrids is a waste of
time, seeing as there's no concrete definition (nor is there ever likely to
be) of what constitutes a specific / generic / familial difference... It
could be argued that Pan and Homo should be one and the same... For what are
(IMHO) reasons of social acceptability they aren't...
Chronology's not reliable either, different taxonomic groups and different
genes evolve at different rates... the origin of an absolute reproductive
barrier (either pre- or post- zygotic) can occur with very little divergence
(and practically no relation to phenotype).