Chromosomes

William Bains william at wbains.u-net.com
Fri Feb 20 09:42:38 EST 1998


In article <34ED491D.3220 at marauder.millersv.edu>,
jmone at MARAUDER.MILLERSV.EDU ("Jay Mone'") wrote:

> Amber,
> I doubt if anyone knows the significance of chromosome numbers in 
> different organisms.  Chromosome number doesn't appear to be directly 
> related to complexity, but rather to overall diversity of species.  
> For example, humans have 46 chromosomes, while dogs and chickens have 
> 78.  Some ferns have over 100.
> 
> Jay Mone'

No-one knows why chromosomes are as they are - it may be related to
'diversity' (although why do restricted and homogenous species like chimp
and gorilla have one more chromosome pair than we do?), but most of it
seems to be evolutionary accident. 

Also, dogs are only highly morphologically diverse, not genetically (they
can  all interbreed easily, providing the smaller one stays still), and
this is driven by very evolutionarily recent human selection anyway.

William Bains



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