Path: news.nzbot.com!not-for-mail
From: "Uncle Davey" <noway@jose.com>
Newsgroups: alt.fan.uncle-davey
Subject: Re: Is there a link between dominance/recessivity of genes and earlier evolutionary forms?
Date: Sat, 28 Feb 2004 22:06:13 +0000 (UTC)
Organization: www.usenetposts.com
Lines: 54
Sender: root@darwin.ediacara.org
Approved: robomod@ediacara.org
Message-ID: <c1r3lj$gpf$0@pita.alt.net>
References: <c1r0vu$btv$0@pita.alt.net> <40410F55.4080000@pacbell.net>
NNTP-Posting-Host: darwin
X-Trace: darwin.ediacara.org 1078005973 82149 128.100.83.246 (28 Feb 2004 22:06:13 GMT)
X-Complaints-To: usenet@darwin.ediacara.org
NNTP-Posting-Date: Sat, 28 Feb 2004 22:06:13 +0000 (UTC)
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2800.1158
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165
Xref: news.nzbot.com alt.fan.uncle-davey:2829
>
>
> Uncle Davey wrote:
>
> > Has anyone done any work on this topic?
> >
> > It seems to me as though the 'wild forms' of animals tend to have the
> > dominant characteristics. When a wild boar mates with a pig, the
offspring
> > have more the shape of a wild boar, there is no fattening them up like a
> > domesticated pig, and so the farmers hate when that happens.
> >
> > Can we see a general tendency that wild characteristics are dominant and
> > ones bred in are nore recessive?
>
>
> Yes, to a degree. Though I'm not sure it accounts for the phenomenon you
> describe. Recessive mutations most commonly are recessive because they
> create a non-functional protein, or no protein at all. So in combination
> with an allele that does create a functional protein, we get a "normal"
> phenotype. Since there are more ways to break a gene than to fix it,
> many mutations are recessive. Breeders work with what they get, and
> sometimes the phenotype produced by rendering a gene non-functional is
> useful in a domestic animal. Thus many of the differences between
> domestic animals and their wild ancestors are probably recessive to the
> "wild type" alleles. On the other hand, many of the traits important to
> breeders are polygenic and quantitative, and the domestic breed has been
> assembled slowly by accumulating alleles at lots of loci that push the
> phenotype all in the same direction. Mixing this with a wild type will
> push the phenotype toward the mean. If, for example, some character
> state, call it A in a domestic animal is influenced by 10 loci eac with
> two alleles A and B, the domestic animal would have a genotype of
> AAAAAAAAAA, while a wild type would be a random mix of As and Bs,
> perhaps tending around 50% each, e.g. AABABBBAAB. A first generation
> hybrid would have around a quarter Bs and might look like a wild type to
> you.
>
I see. It looks like you're saying yes, but with qualifications.
In humans, blond hair is like a recessive characteristic, and dark hair is a
dominant one. Is that because humans came out of Africa? Were humans all
dark haired first, and some became blond later?
And if there's a functional protein in dark hair, why did we lose it, if
it's functional?
Uncle Davey
|
|