Re: NANFA-- Captive breeding

Jeffrey Fullerton (tcmajorr_at_westol.com)
Thu, 24 Feb 2000 16:27:18 -0500

Fish and other creatures have been doing this sort of thing for millions of
years. They don't give a rat's tail about genetics or systematics - they just do
what comes natural and work their way into whatever niche they can get into.
It's not to say that the science behind genetics is not important, but the
deriving of stocks from limited or mixed gene pools is not always detrimental to
the survival of a species. Many species have passed through genetic bottlenecks
before and have survived and reexpanded on their own. many small populations have
been able to remain in good health inspite of inbreeding.
Small villiages of people - the Yanamamo in the Venezuelan rainforest are by our
standards inbred but healthy. They still have an incest taboo but the size of the
population is very small so it is far more genetically uniform. Selection
pressure - including repugnant things like infanticide have culled out harmful
genes that are more likely to run recessively in larger populations.
In human populations - the recommended minimum number of founders (for say for a
repopulate the world or to send a ship to colonize another star system scenario
is about 50 or 60 people) That may be for reasons of supporting a divirsity of
useful tallents as well as social inertia to keep society stable. Some human
populations have made due with less. I had an anthropology professor who said
that incest was not harmful as long as mating remains random.

Now I can just imagine the jokes this post will forment!
Jeff
Moontanman_at_aol.com wrote:

> I would like to put in my two cents worth about captive breed fish not being
> suitable to release into the wild. I have put a little thought into the
> matter and I realized that the differences between captive and wild fish
> might not because of changed or lost genetic materials but because of
> environmentally suppressed genes. My main example is the lowly gold fish. you
> can allow gold fish of the most gnarly warty headed inbreed variety you can
> get to breed freely in a pond and in a few years all you end up with is the
> wild type gold fish. could this be because the genes for the wild type fish
> were not bred out but just suppressed? these fish have been bred in captivity
> for thousands maybe millions of generations but it doesn't take long for the
> goldfishes old genes to take effect. Fish that we breed in captivity for just
> a few dozens of generation should revert back to wild type rather easily.
> maybe someone should try the experiment of stocking a small pond with several
> species of captive breed fish and see if they revert back to the wild type in
> a few generations? I think this might be a worthy experiment.
>
>
> Moon
>
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/"Unless stated otherwise, comments made on this list do not necessarily
/ reflect the beliefs or goals of the North American Native Fishes
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/ nanfa_at_aquaria.net. To subscribe, unsubscribe, or get help, send the word
/ subscribe, unsubscribe, or help in the body (not subject) of an email to
/ nanfa-request_at_aquaria.net. For a digest version, send the command to
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/ For more information about NANFA, visit our web page, http://www.nanfa.org