Mutations Helped Humans Survive Siberian Winters 77
sciencehabit writes "Researchers have identified three genetic mutations that appear to have helped humans survive in the frigid climate of Siberia over the last 25,000 years. One helps the body's fat stores directly produce heat rather than producing chemical energy for muscle movements or brain functions, a process called 'nonshivering thermogenesis.' Another is involved in the contraction of smooth muscle, key to shivering and the constriction of blood vessels to avoid heat loss. And the third is implicated in the metabolism of fats, especially those in meat and dairy products—a staple of the fat-laden diets of Arctic peoples."
Re:Arterial plaque? (Score:4, Informative)
Re:So basically... (Score:4, Informative)
Re:Dairy for 25k years? (Score:5, Informative)
Lactase nonpersistence is the ancestral state, and lactase persistence only became advantageous after the invention of agriculture, when milk from domesticated animals became available for adults to drink..... http://x.co/sfIC [x.co]
Agriculture is absolutely not required for milk to become available for adults to drink.
Animal husbandry is required and you find that in many nomadic, non agricultural, societies.
Re:Some clarifications (Score:4, Informative)
This reasoning is a fallacy.
You can make precisely the same argument about the last common ancestor between humans and chimps, or the last common ancestor of humans and neandertals. In a general context, chimp brain is as complex as ours. Yet evolution happened in between, we can track it, and we can see that it did in fact modify the cognitive functions of that ancestor; chimps are not humans. And hell, even the developmental machinery that makes an egg develop into an adult vertebrate is complex and interdependent, and if what you are quoting were true, one would expect all vertebrate life remain at the stage of a fish.
The actual reason might be much more mundane: the initial small population of modern humans expanded so rapidly that any resultant genetic differences between populations are the result of neutral evolution (like genetic drift) rather than natural selection. This is also why genetic diversity is inversely correlated with geographic distance to Africa. Essentially, we are all still this same small initial population, but we expanded like a balloon, taking down - directly or indirectly - any other populations that might have existed at times (like the neandertals, denisovians and many, many other hominins).