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Re: Neanderthals horse or mule?
Todd A. Farmerie (taf2@po.CWRU.Edu)
2 Oct 1995 07:17:00 GMT
In a previous article, hubey@pegasus.montclair.edu (H. M. Hubey) says:
>sjoland@ix.netcom.com (Peter/Stephen Sjolander ) writes:
>
>
>>We have a modern day example to follow. The donkey and the horse.
>>They can bread and make a mule. But the mule can not bred with another
>>mule and make a mule.
>
>NOrmally that's what happens. some years ago there was a report
>in Science News about a fertile mule found in China. IF they find
>another one, there's the mule species. If not, then they can
>cross it with horses and donkeys and check the results.
>
We are a little bit off topic, but there is a finite, incredibly small
probability that each mule will give birth. This will happen if, and only
if, when meiosis occurs to produce a egg (or sperm) with a single copy of
each chromosome, the mule happens to resegregate the genomes of the two
parents. Such a birth occurs every 3 years or so, world-wide (or maybe
twice that often since its harder to determine if your male mule has
successfully passed on its line that if your female mule has. This will
only happen if the mule is being kept with either horses or donkeys,
because the probability of having both a fertile egg and a fertile sperm in
the same herd of mules at the same time is extremely slim. The progeny
will be either a horse, a donkey, or another mule, depending on which set
of parental genes the fertile egg contains, and which species the mate is,
but if a mule, it will have no higher probability of breeding than any
other mule. Non-parthenogenic animals rarely produce new species by
hybridization, but instead primarily do so by genetic drift. (By the way,
if you want two species (different numbers of chromosomes) that cross breed
and produce fertile offspring, compare the common horse and the Przewalski
horse.)
If you want to consider neanderthals as hibrids, what are the two species
that hybridize to produce them?
Todd
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