genetics

[Alison Murie]

On Apr 29, 2010, at 5:42 PM, victor steinbok wrote:

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> Sender:       American Dialect Society <ADS-L at LISTSERV.UGA.EDU>
> Poster:       victor steinbok <aardvark66 at GMAIL.COM>
> Subject:      Re: genetics
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>
> Actually, the way you describe it, it would have to be recessive,
> e.g., hemophilia. The idea is that because women have a pair of X
> chromosomes, one would carry the dominant gene that blocks the
> disorder--more precisely, in such cases, this gene is functioning
> normally in producing a particular set of proteins--while the damaged
> gene does not produce the proteins. Then, if the damaged gene is
> inherited by male offspring, there is no corresponding normal gene in
> the Y chromosome to offset the damage caused by the defective one from
> the lone X. This is why sometimes women DO end up expressing syndromes
> usually associated with men (colorblindness, hemophilia, baldness).
>
> To be honest, I've seen a lot of conflicting information concerning
> heredity of baldness, so I am not even sure if this claim carries any
> weight. But it still makes a good (peripheral) story.
>
> VS-)
>
> On Thu, Apr 29, 2010 at 4:54 PM, Alison Murie <sagehen7470 at att.net>
> wrote:
>
>> It would have to be carried on the X, or a woman wouldn't have it.
>> Presumably it is dominant, or there would need to be two, one from
>> each parent.  The mechanism may be more complicated, controlled by
>> more than one pair of genes.  I'm no geneticist, just parroting stuff
>> I read somewhere,  confirmed by my biologist husband.
>> AM
>
~~~~~~~~~~~~
Um, you are right, in that it could be recessive, but it wouldn't have
to be.   The offspring could get a recessive from each parent ( the
male having inherited one that was not expressed) & would then express
the baldness.  On the other hand, if it were dominant, it wouldn't
matter what the male contributed.
Of course it isn't really this simple.  The contribution of
environment is incalculable, for one thing.
AM

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