Just like peacocks.
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Replying to @CovfefeAnon
The source of the secondary sexual dimorphism of humans isn't mitochondrial DNA...
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Replying to @CBlossius
So? The reason to look at mtDNA isn't because its a particularly interesting genetic influence on phenotype - it's interesting because it's matrilineally inherited. It's a measure of the variance in reproductive success of women (low var, high) vs men (high var).
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Replying to @CovfefeAnon
"they have in many ways pre-modern brains." You are talking here of sexual dimorphism in the brain. This has nothing to do with mtDNA.
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Replying to @CBlossius
It has nothing to do with mtDNA directly. mtDNA is a tool for measuring the reproductive success of women - if no mtDNA lineages go extinct it means nearly all women are successfully reproducing. Meanwhile, Y chromosomes going extinct means that very few men are - filtered.
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Replying to @CovfefeAnon
I understand, but nothing follows from that about the psychology of the sexes today. Men mate with women and beget daughters as well as sons. Oh well, I'm going to bed
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Replying to @CBlossius
There's a gene that influences some behavior in a way that improves survival when it's found in a man but has no effect when it's in women or even a small negative effect. This gene still spreads b/c there's no pressure on women - nearly all of them reproduce. Peacock / peahen
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Replying to @CovfefeAnon
It may well be, but that's not what those plots you posted show. They're about a single selection event, not persistent pressure, she you spoke of premodern brains in connection with it.
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Replying to @CBlossius
First, there's absolutely no reason a single event can't be a massive selective filter - give a metaphorical test of some kind, failures get killed, successes don't and the resulting population is massively different on that measure. Second, the period shown is a few K years.
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Replying to @CovfefeAnon
There's always a partial regression to the mean. A few thousand years could however change the population significantly. You have to assume that this affected genes with sex-specific pleiotropic effects.
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On the one hand you have this massive, crushing selective pressure *on men* On the other you see nearly all women reproducing It's blindingly obvious that genes that have positive effects *in men* are under selective pressure and their effect in women is irrelevant - random
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Replying to @CovfefeAnon
What makes you think that such genes exist and were among those affected by that particular selection event? It is possible, but not necessary
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Replying to @CBlossius
Because "16 of 17 men died without issue due to randomness" is absurd on its face and we're talking largely about genes for behavior which is always different in every way between men and women.
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