Cultural evolution has been dragging us into new environments of adaptation and selection. Far from replacing genetic evolution, it has caused the human genome to evolve faster.
According to my understanding, evolution requires selection, not just genetic mutation. "Changes to the genome accelerated more than a hundredfold when...". Changes to the genome just means there is more genetic mutation because there are more people. Evolution needs more than that, it needs strong levels of selection for certain mutations.
This is admitted in the article: "A species with millions of individuals has a gene pool of such enormous size that the replacement of a gene by another allele is a very slow process". Right now, we have an enormous gene pool. Right now, there is only weak selection taking place. I am skeptical that evolution has accelerated at all since hunter-gatherer times.
Yes, there are more mutations with a larger population, but only selection can drive those mutations to fixation. You actually make that point, so I'm puzzled by your conclusion: "I am skeptical that evolution has accelerated at all since hunter-gatherer times." If the human genome has been undergoing a faster rate of change, that would surely indicate stronger selection, and not just more mutations.
Right now, there is plenty of selection, but it's for mental traits like extraversion and neuroticism and for physical traits like obesity.
Genetic variability (or rather the lack thereof) has not been a major constraint on human evolution, even in relatively small populations. There has been considerable cognitive evolution among the Parsis and the Ashkenazim, yet both groups were quite small in number during most of their existence.
Matt Osborne,
No, the acceleration began much earlier, and we're still not sure when it ended. In fact, we're just starting to understand human evolution during historic times, thanks to ancient DNA data. In general, it looks like imperialism is bad for cognitive evolution (collapse of fertility among the upper and middle classes, increase in polygyny and female hypergamy, slavery and globalization of labor markets, etc.).
Y chromosome bottlenecks are typical of highly polygynous societies, and such societies tend to be evolutionarily static.
Fascinating work. More like this in the future please. I wonder what the impact of variable mutation rates might be in this kind of dynamic. Systemic stress seems to increase mutation rates, so maybe shrinking populations have a deep mechanism to increase mutation rates in response to give the species more chance of finding useful variants.
Would this have anything to do with the Y chromosome bottleneck in the Old World ca. 5k-3,500k BC? That was a pretty strong selection moment, as I understand.
According to my understanding, evolution requires selection, not just genetic mutation. "Changes to the genome accelerated more than a hundredfold when...". Changes to the genome just means there is more genetic mutation because there are more people. Evolution needs more than that, it needs strong levels of selection for certain mutations.
This is admitted in the article: "A species with millions of individuals has a gene pool of such enormous size that the replacement of a gene by another allele is a very slow process". Right now, we have an enormous gene pool. Right now, there is only weak selection taking place. I am skeptical that evolution has accelerated at all since hunter-gatherer times.
Windsor Swan,
Yes, there are more mutations with a larger population, but only selection can drive those mutations to fixation. You actually make that point, so I'm puzzled by your conclusion: "I am skeptical that evolution has accelerated at all since hunter-gatherer times." If the human genome has been undergoing a faster rate of change, that would surely indicate stronger selection, and not just more mutations.
Right now, there is plenty of selection, but it's for mental traits like extraversion and neuroticism and for physical traits like obesity.
See my article: https://peterfrost.substack.com/p/the-great-decline
Shane Simonsen,
Genetic variability (or rather the lack thereof) has not been a major constraint on human evolution, even in relatively small populations. There has been considerable cognitive evolution among the Parsis and the Ashkenazim, yet both groups were quite small in number during most of their existence.
Matt Osborne,
No, the acceleration began much earlier, and we're still not sure when it ended. In fact, we're just starting to understand human evolution during historic times, thanks to ancient DNA data. In general, it looks like imperialism is bad for cognitive evolution (collapse of fertility among the upper and middle classes, increase in polygyny and female hypergamy, slavery and globalization of labor markets, etc.).
Y chromosome bottlenecks are typical of highly polygynous societies, and such societies tend to be evolutionarily static.
Fascinating work. More like this in the future please. I wonder what the impact of variable mutation rates might be in this kind of dynamic. Systemic stress seems to increase mutation rates, so maybe shrinking populations have a deep mechanism to increase mutation rates in response to give the species more chance of finding useful variants.
Would this have anything to do with the Y chromosome bottleneck in the Old World ca. 5k-3,500k BC? That was a pretty strong selection moment, as I understand.
Let’s go