Mystery humans spiced up ancients’ rampant sex lives (from Nature)
Excerpt: Most surprisingly, Reich said, the new genomes indicate that Denisovans interbred with another extinct population of archaic humans that lived in Asia more than 30,000 years ago, which is neither human nor Neanderthal.
My comment: Is the information on one species of Homo during the past 1.8 million years of any concern here? A Complete Skull from Dmanisi, Georgia, and the Evolutionary Biology of Early Homo (from Science)
Excerpt: “Sabeti and her team found that a previously reported variant of the EDAR gene, which arose in central China about 30,000 years ago, increased the number of sweat glands in genetically modified mice and had other effects not previously reported in humans; their discovery demonstrates that animal models can be used to study the biological changes expected to result from human genetic variation. This gene variant was also associated with an increase in the number of sweat glands in a present-day Han Chinese population. By enhancing sweating, this EDAR variant could have helped humans adapt to humid climates that may have existed in China 30,000 years ago.”
My comment: The confusion about whether one, two, or three different human species existed in Asia 30,000 years ago, appears to pit the fossil record AND what some researchers have learned about molecular epigenetics against the theory of mutation-driven evolution. Others do not seem to be considering any aspect of nutrient-dependent pheromone controlled adaptive evolution, since they are still talking in terms of different human species that probably somehow arose through natural selection.
For example: Nature: “He speculates that the population could be related to Homo heidelbergensis, a species that left Africa around half a million years ago and later gave rise to Neanderthals in Europe. “Perhaps it lived on in Asia as well,” Stringer says.”
Science: “…increased levels of intragroup cooperation (3) might have led to increased rates of reproduction, survival, and mobility in early Homo and the consequent establishment of stable populations outside Africa.”
1) If Sabeti’s variant is nutrient-dependent in this population, it exemplifies adaptive evolution via increased levels of intragroup cooperation in nutrient acquisition that led to increased nutrient-dependent pheromone-controlled reproduction.
2) If Stringer’s variations in species are due to mutations, they would exemplify what no experimental evidence in any species has ever supported: mutation-initiated natural selection that somehow “gave rise to Neanderthals in Europe”.
Of course I am biased in favor of my model and the fact that “Science” has never refused to publish my comments on articles. For comparison, “Nature” abruptly began blocking all of my comments after publishing several that included my conflicting perspectives. Whether human variation is attributed to nutrient-dependent pheromone-controlled adaptive evolution or mutation-driven evolution might best be addressed by first asking the question: “Is there a model for that?”