Re: NANFA-L-- Review of Suckers in North America


Subject: Re: NANFA-L-- Review of Suckers in North America
dlmcneely at lunet.edu
Date: Tue Oct 12 2004 - 14:47:14 CDT


There are several measures of genetic diversity, all of which depend on some sort of genetic analysis of individuals. This gets pretty technical, but one way involves determining enzyme variability across individuals using a technique called protein electrophoresis. Populations with more enzyme morphs are more variable so far as the gene for that enzyme is concerned than are populations with fewer morphs. DNA analysis is also used, including mitochondrial and nuclear DNA.

And yes, data do demostrate that populations with greater genetic diversity pass through selection events more successfully than do populations that are less diverse. That is the tragedy of the monoculture. When a blight hit U.S. corn crops in the late 1970s early 1980s, almost all the feed corn grown here was of one strain, selected for high seed yield. The U.S. contribution to feed corn production tanked, and beef and pork prices both escalated. But the industries recovered eventually because other corn strains did exist. The few farms growing old, open pollinated corn did better than others.

Works on the individual level, too, where it is called "hybrid vigor." Heterozygotes may have advantages due to the products of their two alleles for a gene. A classic example in humans is that the heterozygote for sickle cell hemoglobin and normal hemoglobin is superior to either homozygote because it is resistant to the malaria parasite, and does not suffer from sickle cell anemia either.

David L. McNeely, Ph.D., Professor of Biology
Langston University; P.O. Box 1500
Langston, OK 73050; email: dlmcneely at lunet.edu
telephone: (405) 466-6025; fax: 405) 466-3307
home page http://www.lunet.edu/mcneely

"Where are we going?" "I don't know, are we there yet?"

----- Original Message -----
From: Irate Mormon <archimedes at bayspringstel.net>
Date: Tuesday, October 12, 2004 2:04 pm
Subject: Re: NANFA-L-- Review of Suckers in North America

> Quoting "dlmcneely at lunet.edu" <dlmcneely at lunet.edu>:
>
> > Natural selection for success in hatcheries? Less genotypic
> variability?
> > Hatchery fish are the progeny of a restricted set of parents
> compared to wild
> > fish.
>
> Has anybody been able to demonstrate that genetic variability has
> a measurable
> impact on either long or short term survival? How do you measure
> geneticdiversity within a population?
>
> Do the data suggest that older, more experienced fishes have trouble
> "unlearning" the bad habits they pick up when raised in captivity?
> If so, then
> I like Moon's idea. Release 'em when they're real tiny, before
> they have a
> chance to learn anything.
>
> --Irate
> Where am I going? And why am I in this handbasket?
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: Fri Dec 31 2004 - 11:27:44 CST