Re: NANFA-L-- Re: the aquarium hobby as conservator of

J. C. (
Sat, 13 May 2006 10:48:32 -0700 (PDT)

I was taught that what you speak of is pheno types
showing up under different enviroments. I bet if they
did genetic test on the fish the genes would be the
same. Genes do not change in one generation from the
wild caught fish. They may look totally different
because of the different enviroment but genetic
changes take time.

Later, John

--- Steffen Hellner <> wrote:

> To me genetics is overestimated. Look-in-Cyprinodon
> diabolis. Extremely
> small population, isolated for aeons, when released
>-in-Hoover Dam it
> suddenly developed the ancient body shape and size
> back. If that inzest
> doesn4t eliminate the ancient form over thousands of
> years, what can captive
> rearing for some generations mean? Not much from my
> point of understanding.
> If there is no competition then genes are extremely
> lazy in regard of
> changing.
> Am 12.05.2006 19:33 Uhr schrieb "Jerry Baker" unter
> <>:
> > wrote:
> >> I have to disagree, release a large number of
> domestic goldfish into the
> >> wild, in a pond or even a stream. In a very few
> generations you will have
> >> wild
> >> type goldfish again. I've seen it happen in even
> small ponds. animals are
> >> often
> >> genetically more plastic than we give them
> credit for.
> >
> > Indeed. The whole argument that captivity induces
> genetic drift, and
> > therefor bad, is a tautology. Of course there is
> genetic drift because
> > that's what happens when one population of a
> species is separated from
> > another. It might not have anything to do with
> captivity and just be the
> > process of natural evolution continuing along
> slightly different courses
> > in isolated populations. Sure, the conditions of
> captivity can influence
> > the evolutionary path, but that shouldn't matter
> much as long as the
> > animals remain able to survive in their natural
> environment. Without
> > constantly providing for genetic exchange between
> two populations held
> > in isolation, of course they're going to drift.
> Keep them separated long
> > enough and they may evolve into separate species.
> That's the way it works.
> >
> > It seems to me that trying to keep a population of
> some threatened or
> > endangered creature genetically stable is as
> foolish as was the old way
> > that the National Park Service used to try and
> prevent any changes in
> > the forests. After a while the exclusion of fire
> and other disturbances
> > was destroying the very forests they thought they
> were protecting. I
> > don't think it would be helpful to actively
> prevent a species from
> > experiencing the genetic drift that might allow it
> to adapt and survive.

John Cox of Cumberland Killifish
Honey Robber beekeeping and removal services

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