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I'm not so sure. For example, the Tibetan adaptations to altitude are much better than those in the Andes... and when last I checked it was thought that this mi

by iguy 9y ago

I'm not so sure. For example, the Tibetan adaptations to altitude are much better than those in the Andes... and when last I checked it was thought that this might come from Neanderthal or Denisovan ancestors. Or last week's news about adaptations to diving -- one tiny niche which happens to be relatively easy to study: https://news.ycombinator.com/item?id=16883566 https://news.ycombinator.com/item?id=16883566

Symmetry 9y ago
And I was very surprised by the diving adaptation story last week until I got to the part where they found that the adaptation was just a single gene. And I wouldn't be surprised that some environmental adaptations might be better than others given that relatively little evolutionary time has passed and the barriers for the transfer of altitude adaptations from one high altitude region to another. But there are no such barriers to the transfer of IQ enhancing alleles, those will help you everywhere.
- iguy 9y ago
  OK, single gene effects are the easy ones to find, so we find them first. We know height is massively polygenetic though. The point of the Tibetan story is that they (may) benefit from > 200k years of adaptation to that geography, via these ancestral humans. Whereas the Andean people had < 10k years. Re transfer of IQ, why is it always beneficial? There are always trade-offs -- more blood to the brain is going to make it harder to survive famines, for instance. Some monkey species are dumber than others because it was not profitable in their niche. Domesticated herbivores are dumb too. It could be that this doesn't apply to us, e.g. if we are the result of some recent breakthrough.
  - Symmetry 9y ago
    There are certainly tradeoffs with IQ. There one allele that raises your IQ a bunch but has a good chance of causing you to die early. And if you had a domesticated species of human I'd expect that that might hurt intelligence. But given that humans' primary competition has been other humans and given that this is true the world over I expect that IQ would be roughly equally valuable everywhere and so we shouldn't see big differences, genetically, between populations like you do with adaptations to other sorts of particular environments.
    - iguy 9y ago
      In the western word, today's environment seems to select against IQ -- number of children anti-correlates. This wasn't true 200, 300 years ago. So that's one example of two environments which value this trait very differently. Sure, one of them is highly unusual... The flores island hobbits are another example, where it seems that humaniods evolved quite dramatically smaller brains. But islands are also unusual, obviously.

by iguy 9y ago

Symmetry 9y ago

And I was very surprised by the diving adaptation story last week until I got to the part where they found that the adaptation was just a single gene. And I wouldn't be surprised that some environmental adaptations might be better than others given that relatively little evolutionary time has passed and the barriers for the transfer of altitude adaptations from one high altitude region to another. But there are no such barriers to the transfer of IQ enhancing alleles, those will help you everywhere.

iguy 9y ago
OK, single gene effects are the easy ones to find, so we find them first. We know height is massively polygenetic though. The point of the Tibetan story is that they (may) benefit from > 200k years of adaptation to that geography, via these ancestral humans. Whereas the Andean people had < 10k years. Re transfer of IQ, why is it always beneficial? There are always trade-offs -- more blood to the brain is going to make it harder to survive famines, for instance. Some monkey species are dumber than others because it was not profitable in their niche. Domesticated herbivores are dumb too. It could be that this doesn't apply to us, e.g. if we are the result of some recent breakthrough.
- Symmetry 9y ago
  There are certainly tradeoffs with IQ. There one allele that raises your IQ a bunch but has a good chance of causing you to die early. And if you had a domesticated species of human I'd expect that that might hurt intelligence. But given that humans' primary competition has been other humans and given that this is true the world over I expect that IQ would be roughly equally valuable everywhere and so we shouldn't see big differences, genetically, between populations like you do with adaptations to other sorts of particular environments.
  - iguy 9y ago
    In the western word, today's environment seems to select against IQ -- number of children anti-correlates. This wasn't true 200, 300 years ago. So that's one example of two environments which value this trait very differently. Sure, one of them is highly unusual... The flores island hobbits are another example, where it seems that humaniods evolved quite dramatically smaller brains. But islands are also unusual, obviously.