Natural selection will be out the window. It will be replaced entirely by intentional selection. We will certainly see new diseases rooted in human vanity and hubris, and they will become business opportunities for surgeons and pharmacists, just as our natural and lifestyle ailments have become moneymaking industries.
So the great-grandchildren of people that were gifted by their parents with then-fashionable gene mutations will have all new reasons to pay for health care.
And Sylvester McMonkey McBean simply unveils his star-off machine.
Evolution does not vet for anything except population-level viability. Once upon a time, our population bottlenecked. The return of large-scale genetic diversity is normal for an animal species, especially one that has spread to practically every environment on the planet.
Also, evolution is not a prescriptive standard. Oy.
You haven't talked with my knees recently, have you.
-Another strongly supported hypothesis is that there was an near-extinction event that wiped out all but a pocket of human settlements from which we descended. - The diversity in other species that are about as old as ours is significantly far greater than ours suggesting that it is more likely an event like an unusually strong ice-age period that could've worsened our genetic diversity.
-It's unlikely that the Toba catastrophe was the root cause of the bottleneck as reasoned in this investigation:
https://www.livescience.com/29130-toba-supervolcano-effects....
- I wonder if the hypothesis of leaving Africa in small groups could be effectively tested.
Specifically, modern humans have, on average, less than 0.1% of differences in their DNA amongst each other: "How diverse are we? Perhaps the most widely cited statistic about human genetic diversity is that any two humans differ, on average, at about 1 in 1,000 DNA base pairs (0.1%). Human genetic diversity is substantially lower than that of many other species, including our nearest evolutionary relative, the chimpanzee. Genetic diversity is a function of a population's "age" (i.e., the amount of time during which mutations accumulate to generate diversity) and its size. Our genetic homogeneity implies that anatomically modern humans arose relatively recently (perhaps 200,000 years ago) and that our population size was quite small at one time (perhaps 10,000 breeding individuals). To put the 0.1% genetic diversity estimate into perspective, it is useful to remember that humans have approximately 3 billion base pairs in a haploid cell. Thus, any pair of humans differs by approximately 3 million base pairs. These differences contain much useful information about the evolutionary history of our species. In addition, the small proportion of differences that occur within genes can lead to critical inferences about the effects of natural selection. "