Re: 50% mutation
From: Guy Hoelzer (hoelzer_at_unr.edu)
Date: 02/22/05
- Next message: Guy Hoelzer: "Re: Lottery tickets"
- Previous message: William Morse: "Re: Logic of kin selection"
- In reply to: A.C.H.: "50% mutation"
- Messages sorted by: [ date ] [ thread ]
Date: Tue, 22 Feb 2005 01:25:15 -0500 (EST)
in article cvb06a$rhm$1@darwin.ediacara.org, A.C.H. at br.hessels@planet.nl
wrote on 2/20/05 1:41 PM:
> A lot of evolution is the result of quantitive changes. In human
> evolution, for example, more brain, less hair, less snout etc. etc.
>
> These changes are the result of changes in the regulation of genes;
> how much, when and where a certain gene-product is produced. (And not
> of changes in the gene-products themselves.)
Some organismal mutations are the result of mutations of the genes
themselves, too. The proportional importance of this class of mutations is
not clear.
> The thing i want to point out is that the variables more-less,
> earlier-later are one-dimensional. A mutation in a regulatory sequence
> results in a phenotypic change along one dimension.
This is rarely the case. Why do you think that a change in a regulatory
sequence would only influence one dimensional of the phenotype? Pleiotropy
(one gene, or one mutation in this case, influences multiple dimensions of
the phenotype) seems to be the rule.
> Now consider a situation of directional selection, a situation where
> some adaptive change is required.
I presume you meant "favored" rather than "required".
> The chance of a favorable mutation, a mutation with with positive
> fitness, is exactly 50%. (since either more or less, earlier or later
> necessarily results in positive fitness.)
>
> Am i missing something?
I think you are missing plenty. If you tinker with a well-designed,
functional machine you are almost inevitably going to make it worse. You
only have a 50/50 chance of making it better if the "machine" were only a
random collection of parts and connections to begin with. Of course, the
machine would have to be much more thoroughly designed than that to function
at all.
Cheers,
Guy Hoelzer
- Next message: Guy Hoelzer: "Re: Lottery tickets"
- Previous message: William Morse: "Re: Logic of kin selection"
- In reply to: A.C.H.: "50% mutation"
- Messages sorted by: [ date ] [ thread ]
Relevant Pages
|
|
