Re: Intelligence on the X chromosome
Matt Beckwith (beckwith@jaxnet.com)
18 Aug 1996 02:27:44 GMT
catherine yronwode <yronwode@sonic.net> wrote:
>Matt Beckwith wrote:
>
>> What is true about X-linked traits, however, is that, if the trait is
>> a recessive one, it will show up in all men who have it, and a very
>> small minority of women who have it (only those women who have the
>> same gene on both of their X-chromosomes). I doubt that intelligence
>> genes are recessive genes, but if they are, its presence on the X
>> chromosome would explain why men are smarter than women (just kidding,
>> just kidding).
>
>Actually, the multiplicity of these genes and the presence of all of
>them on the X chromosome was hypothesized by the researchers to account
>for the fact that women's intelligences tend to cluster around a
>bell-curve average but men have a split-pattern distribution of
>intelligence, including more retarded and more genius level minds than
>women.
Now, come on, where's the smiley face....?
I resemble that remark! :)
So, if I understand correctly, the fact that women have twice as many
alleles would tend to increase the probability of their distribution
being a normal one. Yeah, that makes sense. So a woman is less likely
to have all high-intelligence genes or all low-intelligence genes.
This pretty well implies that these genes are not recessive, but
co-dominant.
I wonder what the evolutionary advantage is in having these genes on the
X chromosome.
--
Matt Beckwith
http://users.southeast.net/~beckwith/
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