Blacks have higher pulses of growth hormone than whites do and much of what makes their appearance distinctive is similar to changes seen in acromegaly: thick hair and dry skin, loud, deep voices, large hands.
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Among Europeans specifically there are several populations that display unusually thick hair, thick eye brows, reputations for fast anger and an aptitude for music, dancing, and boxing. You particularly see this type in the fish eating Spanish, south Italians and Cretans.pic.twitter.com/4dm8sluv2H
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But the group that stands apart from their close neighbors in all these ways the most starkly are the Irish. However, they’re very different from the all populations mentioned so far: way up north, little sunlight, not much fish consumption now or in the past.
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The primary clue to uncovering what’s happened is that the Irish represent a European extreme in two other ways: unexposed skin that is lighter than any European people, even Scandinavians, and a continent high frequency of hemochromatosis (iron overload).
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Both of these distinctive features act to preserve bone health under conditions of very high rainfall and little sunlight. Those with light skin are able to produce more Vitamin D after exposure to sunlight than the competition: https://www.researchgate.net/profile/Etienne_Cavalier/publication/258054176_Skin_Color_Is_Relevant_to_Vitamin_D_Synthesis/links/544a06e60cf2ea65413426e5/Skin-Color-Is-Relevant-to-Vitamin-D-Synthesis.pdf …
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The European locale that most closely resembles Ireland on maps of rainfall and sunlight is Iceland, which more extreme in both dimensions. Icelanders have also been found to possess abnormally high iron stores:https://www.sciencedirect.com/science/article/abs/pii/089543569190090V …
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I think Ireland and Iceland, both rain soaked and sunless, may be the only two places on earth where alcoholism was selected for because consumption linearly increases ferritin stores in blood. An old farmer may have found it easier to get a hold of booze than animal protein.
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Icelanders don’t have problem drinking rates higher than other Europeans, but this is confounded by the fact that they enforced prohibition until NINETEEN EIGHTY-NINE. I don’t think they were just being sticklers: there is something funny going on here.
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But circling back to the main point: In Coon’s The Races of Europe I believe the Irish are the only group singled out for the thickness of their bones and part of the mechanism has probably been a ruthless selection for both light skin and high baseline levels of Vitamin D.
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D helps protect Irishmen against rickets and inflammatory diseases, but an expected benefit of the selection was this it provided them with a stronger immunity to schizophrenia than any other North European people. Psychotism is a plus if your body can handle it and they could.
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An indicator of how ruthless selection was for skin color specifically can be seen in the contrast between extremely light Irish skin, moderately light eyes, and their surprisingly dark hair. Black Irish hair color may also have a different cause, mediated by dopamine>ACTH.pic.twitter.com/cLWEyxnCrD
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One manifestation of excessively high glucocorticoids like ACTH is Cushing’s Syndrome, whose symptoms are described by Wikipedia in the following way:pic.twitter.com/UIN0wMltDy
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So are there populations that have gone the other way: where selection against schiz has taken place? You would expect it to happen in urbanized places of the far north and there is some evidence in the clump of low hanging dots in the CEU sample here.pic.twitter.com/UUocVkP85U
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About ¼ of Mormons have Scandinavian surnames, principally Danish and Norwegian, and I think the low hanging cluster of dots on the bottom of CEU represents individuals of majority Scandinavian descent that I know to exist in the dataset.
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Scandinavians are under strong selective pressure to keep schizophrenia low, but their high consumption of fish both reduces the power of that pressure and redirects it away from acting directly upon schiz causing alleles and instead improving omega-3 metabolism instead.
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The population that has probably been under the most ruthless selection again schiz per se are the Finns, who along with their Estonian cousins have the highest PISA scores in Europe. Pfiffer also calculated them as having highest the Edu Attainment PGS of any Europeans.
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Schizophrenia risk increases with every IQ dropped and the same genes that increase schiz risk also impair mental function in normals:https://www.nature.com/articles/s41380-018-0332-x …
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Selection against nuttiness may also help to explain the distinctive Nordic personality: in other words, why they’re so boring. The positives to being sane are obvious; the downsides are that you find yourself living in a country where people stare at a burning log on Christmas.
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There's a lot more to write about this, but these are the big points. In my next dealie I'm going to try to figure out what changed around 1985 that led to the current autism explosion and explain how it affected even non-autistic millenials.
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End of conversation
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