-What do these differences in SNP frequencies mean in practice?? We ... don't know yet. At least some population differences are fairly well-understood: I'd tell you about sickle-cell and lactase persistence, except [then I would have to scream](/2017/Dec/interlude-xi/). There are some cases where we see populations independently evolve different adaptations that solve the same problem: people in Tibet and Peru and Ethiopia have
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-[Tibet, Peru, Ethiopia all have high-altitude adapatations, but they're different adaptations, p. 198]
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-The third part of the book is about genetic influences on class structure!
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-[p. 212-4: A + C + E model and comparing identical and fraternal twins (different from twins raised apart)]
-[ACE model assumes no assortative mating, which leads to an underestimate of A: because it makes fraternal twins resemble each other for non-environmental reasons]
-[equal environments assumption could be violated]
+What do these differences in SNP frequencies mean in practice?? We ... don't know yet. At least some population differences are fairly well-understood: I'd tell you about sickle-cell and lactase persistence, except [then I would have to scream](/2017/Dec/interlude-xi/). There are some cases where we see populations independently evolve different adaptations that solve the same problem: [people living on the plateaus of both Tibet and Peru have both adapted to high altitudes](https://www.pnas.org/content/104/suppl_1/8655.long), but the Tibetans did it by breathing faster and the Peruvians did it with more hemoglobin!