🚀 go-pugleaf

In article <26700@boulder.Colorado.EDU>, binkley@boulder.Colorado.EDU (Jon Binkley) writes:
> In article <26689@boulder.Colorado.EDU> I wrote:
>  
>>Ah, but horses and donkeys have different numbers of chromosomes as well.
>>This makes their hybrids sterile, but they are viable.  I don't remember
>>the numbers and I'll try to find out.  They are off by one pair, I believe,
>>similarly to humans/apes.  Of course this proves nothing; but differing
>>chromosome numbers is not sufficient to prevent interspecies crosses.
> 
> Found a reference-- _An Atlas of Mammalian Chromesomes_,
> compiled by T.C. Hsu and Kurt Benirschke, Springer-Verlag, 1967.
> 
> Donkey's have 62 (31 pairs), horses have 64 (32 pairs).  Presumably
> two horse chromosomes are similar to one large donkey chromosome;
> the atlas shows their keryotypes, but I'm no cytologist.
> 
> Obviously, there is sufficient homology for the chromosomes to
> line up properly at mitosis.  Meiosis and gamete formation are
> screwed up though, so mules and jennies are sterile (usually). 
> 
>>I'd bet 5 cents that a chimp/human hybrid would be viable, making humans
>>and chimps, by definition, the same genus.  I also hope I'm never proven
>>right.
> 
> As I said, I'm no cytologist, but the keryotypes of horses and donkeys
> look less similiar to me than the keryotypes of humans and chimps, also
> shown in the atlas.  I raise my bet to 10 cents!
> 
> -jon

Could some of the biologists out on the net comment on this?  I found it of
great interest.  If you can explain why chimp/man would not be inter-fertile
then please do so.  And in layman's terms, please.  If keryotypes are simular
what would need to be dissimular to prevent conception?  I also am willing to
consider immunological responses on the part of the host mother.