What mechanisms have (theoretically) led to genetic changes since Mitochondrial Eve, especially other than mutations? According to the Wikipedia article on ME mutations occur in mtDNA approximately every 3500 years. My advisor calls this “random noise.” However, I’m also aware of a study which found that lactase persistence through adulthood may have emerged within the last 5-10k years, which would apparently be inconsistent with the random noise hypothesis, indicating other mechanisms for adaptation may be at work.
This question is asked purely out of curiosity. To pique yours I will ask, according to modern theories of selection what is the timescale that brain evolution has occurred on? Have brains been the same for the last 50-100k years, with differences in culture being the only change relevant to intelligence, or were changes to neural architecture needed over and above learning based on the environment encountered? To get even more concrete, is it possible that Neanderthals weren’t as smart as Homo Sapiens, and even further, that Homo Sapiens Sapiens are even smarter than Homo Sapiens? Here, “smart” is controlling for culture, i.e., if you were to transplant a newborn Neanderthal into modern culture, is it possible, based on modern theories of selection, that they would have been seen as less intelligent than us?