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The didn't decide, they observed; consistent directional pressure over thousands of years is strong evidence that an allele is being selected for.
So if it survives it's fit, if it's fit it survives? The old tautology
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To be clear: most people who are keen on making such an argument, or who are identifying racial genetic differences as the primary takeaway of studies like this, are doing so to justify racism, either implicitly or explicitly. But that's a strawman. Racism is wrong, even if there are minor genetic variances across populations (which... seems obvious?) Variance within a population strongly dominates the weak cross-pop…
And yet you are also likely to argue “weather is not climate”. Differences in population characteristics of all kinds have massive societal implications and we should lean into addressing them.
If you’re talking about trying to improve the genetics of populations at scale… yikes.
Earlier quoted context omitted.
The didn't decide, they observed; consistent directional pressure over thousands of years is strong evidence that an allele is being selected for.
So if it survives it's fit, if it's fit it survives? The old tautology
Earlier quoted context omitted.
The didn't decide, they observed; consistent directional pressure over thousands of years is strong evidence that an allele is being selected for.
So if it survives it's fit, if it's fit it survives? The old tautology
It's like holding a large ball in place on a hill that sees frequent tremors. If the ball is still halfway up the hill it's being held in place, if it's being held in place it's still halfway up the hill. It might be considered a tautology if you're only working with symbols and ignore all the mechanistics.
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Not a tautology but a definition. https://en.wikipedia.org/wiki/Fitness_(biology)
But other than it surviving, there's no way to define fitness.
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So if it survives it's fit, if it's fit it survives? The old tautology
Whatever does not survive stops registering in later times; most of the time, what helps survival is retained, and what helps survival is what increases fitness.
That is, traits that stop registering may no longer be something that helps survival. But that does not mean they were not necessary for survival at an earlier point.
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I think they're talking about this bit: > We finally observed signals of selection for combinations of alleles that today are associated with three correlated behavioural traits: scores on intelligence tests (increasing γ = 0.74 ± 0.12), household income (increasing γ = 1.12 ± 0.12) and years of schooling (increasing γ = 0.63 ± 0.13). These signals are all highly polygenic, and we have to drop 449–1,056 loci for the…
I haven’t had time to really dig in to the paper but these data (from only one region) are limited in their ability to compare regions, right? If anything they seem to support homogenization of intellectual capacity/mental health in Eurasia since 2kya. The methodology, if it holds up, seems to hold a lot of promise for answering questions like this in the future.
> Just because an allele, SNP, or trait swept into or out of West Eurasia during this time doesn’t mean this happened only in West Eurasia. Researchers can use the new computational methods to look for directional selection in other populations worldwide that have enough ancient DNA sequences and construct a clearer picture of what’s unique to different groups and what generalizes across populations.
> Reich expects that future studies will show that shared selective pressures acted on some of the same core traits across diverse human groups, even as those groups split off and migrated to different parts of the world over tens of thousands of years.
https://hms.harvard.edu/news/massive-ancient-dna-study-revea...