polyploidy/aneuploidy/euploidy

Nancy S. Kirkpatrick nkirkpatrick at GW.LSSU.EDU
Fri Sep 3 12:18:35 EST 1999


Yes, Dave Williams is correct.  Weaver & Hedricks in "Genetics" define
euploid as a polyploid organism whose chromosomes number is an integral
multiple of the chromosome number of the organism from which it
derived.  An example of aneuploidy would be Down syndrome individuals
who inherit an extra copy of chromosome 22 from their birth mother due
to nondisjunction during meiosis.
Are there any zoologists out there?  Carp have 104 chromosomes and a
fisheries biologist I know suspects that this might be due to a
polyploid event.  104 seems like a lot of DNA for one little old fish.

Nancy Kirkpatrick
Biology Dept.
Lake Superior State University
Sault Ste. Marie, MI  49783
PROFDHW at aol.com wrote:
> 
> 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

-- 
Nancy S. Kirkpatrick, PhD.
Assistant Professor &
Chief Health Professions Advisor
Biology Department
Lake Superior State University
Sault Ste. Marie, Mi  49783
(906) 635-2894 FAX: (906) 635-2266
nkirkpatrick at gw.lssu.edu



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