FW: Inbreeding

Charles Miller rellim at mailhost.tcs.tulane.edu
Mon Jun 19 10:41:27 EST 2000

From: Carlos Barata <cb5 at stir.ac.uk>
Date: Mon, 19 Jun 2000 15:37:12 +0100 (BST)
To: rellim at mailhost.tcs.tulane.edu (Charles Miller)
Subject: Re: Inbreeding

You wrote
At 04:00 PM 6/16/00 +0100, you wrote:
>Hi Adam,
>You wrote...
>> I was wondering if there is any information what
>> sort if information is out there concerning the use of inbred stocks of
>> fish in toxicology. Does the use of highly inbred stains of model
>> organisms (ie zebrafish, medaka) effect its response to toxins and may
>> therefore influence these toxicity studies on these fish. Thanks for
>> any information you may give.
>I was not aware that the zebrafish and Medaka were typically  "highly
>inbred". People in the labs here at Tulane U. who maintain zebrafish and
>Medaka colonies typically obtain them from Carolina Biological and other
>suppliers. They breed the fish and continue to obtain new fish. In other
>words, they make no effort to select for any phenotypic traits as they
>propagate the fish and conduct experiments. So I would say that these
>strains are not highly inbred in comparison to mice or rat strains. If you
>are talking about genetically engineered strains of fish then this is
>obviously not the case; they are highly inbred.
>Of course, reducing genetic variability in a population (by inbreeding) is
>likely to restrict the range of toxic responses. Have you obtained different
>batches of fish and observed variable results? If so, you should be able to
>crossbreed the new fish with fish from previous experiments and determine if
>the trait (toxicity?) is genetically dominant or recessive.

I am not working in particular with fish but I am studying genetic
variability in population responses to toxics and its implications for
toxicity tests. I agree with Adam that most of the populations used for
toxicology testing are inbreed or highly genetic homogeneous strains. This
means that in general the response of laboratory populations to toxicants is
quite narrow, in terms of variability, in relation to field populations.
Furthermore acute responses of laboratory populations can be quite
differente from field populations due to inbreeding. Studies supporting my
argument can be found in Barata, C. et al (Aquatic Toxicology 1998,
Functional Ecology 1998, two new papers are coming this year on in ETC and
other in Functional Ecology, You can also look for papers in Functional
Ecology from Valery Forbes, Donald.J. Baird., Festing, M.F.W., 1987. Genetic
factors in toxicology: Implications for toxicological screening. CRC Crit.
Rev. Toxicol., 18: 1-28....

Best regards


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