Re: Fw: [Genetics-Psittacine] What's in a name?
- At 16:15 31-8-2001 -0400, you wrote:
>Message text written by INTERNET:Genetics-Psittacine@yahoogroups.comDeon,
>>>Will you please elaborate on selective types, what exactly is meant by
>that. Do you mean that one allele may have different colour morphs due to
>the action of modifiers, and that one colour morph may be isolated and
>selectively bred by having it possessing an aggregate package of modifiers
>in the closed population?<<
>You've perhaps overstated it a little using the words 'different colour
>morphs' , but I think this is essentially what Inte is saying. Many genes
>vary in their expression depending on their interaction in a particular
>genetic setting. By manipulating that genetic setting by inbreeding and
>selection a breeder can, so to speak, 'choose' a favoured expression of
>that gene and 'fix' it within the closed inbred population.
>This has many similarities with the way exhibition breeders create their
>strains of birds which can be quite dramatically different to the overall
>population. And the pinnacle of such achievements is the development of the
>enormous variety of dog breeds.
>In such cases however the 'improvements' are very quickly lost when these
>selected forms move from the controlled environment and interbreed with the
>general population. They 'revert to type'.
>Unless the originator of a selected form can persuade others of its special
>nature and encourage them to take up its breeding it can have no long term
>>>If I understand it correctly, this poses a very interesting situation
>with the American and S.A. Pieds. Say they are the same mutation that have
>evolved separately in two completely unrelated closed populations. They
>should then each have its own set of modifiers established in each
>respective population pool as we must accept that both strains evolved in
>closed populations. It is then quite possible for each to have a unique
>appearance. When interbred the modifiers will become mixed up and some will
>not be expressed in the first generation, producing pied offspring that
>have a different phenotype to the original pools respectively. <<
>That is the conclusion I believe many of us have reached on the evidence
Clive understood me vey well. I couldn't have said it better myself.