Fri Sep 3 10:41:45 EST 1999

In a message dated 09/03/1999 9:19:53 AM, Dr. Gary Coté writes:

>I've always assumed it... [that plants show polyploidy
>more than animals do]... was simply that animals do not
>tolerate aneuploidy and wind up dead.  That leaves
>the question of why plants can tolerate it and animals
>can't. I've often wondered about that.

But... isn't polyploidy euploidy? I always thought that aneuploidy was the 
absence of even sets, like a partial set (or extra chromosomes which, I 
think, says the same thing).

The American Heritage Dictionary defines aneuploid as:  "Having a chromosome 
number that is not a multiple of the haploid number for the species."

haploid = single-ploidy (-oid = like or appearing as); one full set
diploid = double-ploidy; two full sets
polyploid = many-ploidy; three or more full sets
euploid = good-ploidy; any number of full sets
aneuploid = not good-ploidy; incomplete set (or sets) is (are) present

Any trisomy, for example, is aneuploid (with one incomplete set).

I, also, am wondering why plants are more tolerant of polyploidy. Perhaps 
they aren't. Perhaps it's just a mechanistic, evolutionary "luck of the 
draw". What evidence do we have that animals don't tolerate polyploidy?

Dave Williams
Science Department
Valencia Community College, East Campus
701 N. Econlockhatchee Trail
Orlando, FL  32825
profdhw at aol.com
407-299-5000 x2443

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