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I'm looking at this Ted talk about a Saudi Arabia woman who dared to drive a car in the last few years. This reminds me that until the last century or so, women (all over the world?) enjoyed less rights and might've been pigeonholed into roles predetermined by society. Those roles might've encouraged certain traits, and discouraged others. Those who did not conform might've been punished, like the woman in the talk above received death threats and was jailed.

This sounds to me like selective pressure, did it really exist, and did it have any effect on the genetics/traits of modern women?

This makes me interested in the question - compared to other species, are men and women more genetically different because of selective pressure put on women to conform to male-dominated world for thousands of years before 19th century?

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    $\begingroup$ Males and females have essentially identical genomes (differing only in the very small Y and mitochondrial chromosomes), so they essentially don't differ at all. This is true in other mammals too. $\endgroup$
    – mgkrebbs
    Jun 17, 2013 at 0:05
  • $\begingroup$ Since asking this question, I've learned that there's a massive amount of differences between male and female cognition, as explained by Evolutionary Psychology. $\endgroup$
    – Alex Stone
    Apr 27, 2016 at 14:33

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I'm not sure I buy your premise: firstly, the degree and form of male-female differentiation in social roles has varied widely across time and culture in human history so I doubt it forms a uniform evolutionary driver such as you describe. Secondly, the degree of male-female differentiation appears to me to be much greater in species such as gorillas, lions and peacocks than it does in humans so I'm not convinced that humans would stand out on this front as a species we'd expect to have greater genetic differences.

Even so, the only genetic difference between male and female humans is the Y-chromosome. The X appears in both males and females and doesn't have exclusively female lineage so it can't acquire separate genes for male and female. The Y chromosome contains very few genes so its not capable of manifesting a major genetic gap and because there is no recombination in the Y chromosome it is not a fertile ground for new genes anyway.

So males and females have essentially the same genes. However, this isn't the whole story because how, when and whether genes are expressed is about as important as what genes are encoded anyway. It is these differences that enable big differences between the sexes not actual coding differences.

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  • $\begingroup$ It would be interesting to check (maybe someone has already, I don't know) whether the epigenome of men and women is different! $\endgroup$
    – nico
    Jun 18, 2013 at 6:33
  • $\begingroup$ They are different. Google 'sex differences in epigenetics' and you'll see there's quite a few papers on the subject. It's not my area so I won't claim to know the details. $\endgroup$
    – Jack Aidley
    Jun 18, 2013 at 10:05
  • $\begingroup$ If I understand your answer correctly, because most of the genes(that matter) are in the X chromosome, then selecting for a specific trait in females would also produce it in males, because it's most likely that the X chromosome would be involved. Is this correct? $\endgroup$
    – Alex Stone
    Jun 19, 2013 at 13:37
  • $\begingroup$ Almost. Because genes can be differentially expressed you can still get differences in males and females even though they both share (almost) the same genes but there can't develop a major gap between male and female genomes because they share almost all the chromosomes. The Y chromosome is the only exception but it's not a healthy chromosome because it is exclusively passed down the male line and thus can't rely from recombination to "repair" damaged genes and shuffle genes into new contexts. $\endgroup$
    – Jack Aidley
    Jun 19, 2013 at 13:43
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Essentially, what makes a (mammalian) man a man is a small region on the Y-chromosome called SRY. If this region is deleted, a female phenotype having XY-chromosomes develops. If this region is translocated to an X-chromosome, a male phenotype with two X-chromosomes develops. Other than that, the Y-chromosome does not carry a lot of genes.

So apart from the Y chromosome, males and females are genetically very similar and more similar compared to other species.

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  • $\begingroup$ Are men and women not identical except the Y-chromosome (Not only similiar)? $\endgroup$
    – mart
    Jun 17, 2013 at 6:23
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    $\begingroup$ Similar in the sense of interindividual differences in the genotype. If we were identical, we'd be clones. $\endgroup$
    – Eekhoorn
    Jun 17, 2013 at 7:32

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