Interesting post about genetics in r/africa for once.

He's not right.

Genetic distance increases when two populations are separate and they accumulate different mutations. It goes down when they intermix, form a new mixed population and natural selection works on the new combination just as it did on the previous two populations. Africa is more diverse because populations had less complete mixing or population replacements unlike in eurasia or the americas. This is in part because of the Sahara, the main component eurasian branch of humans is a branch off of a north of the sahara population, most of the genetic contribution of the population europe, asia, ameria and polynesia has had less time to mutate seperately than separated groups in Africa. Going through claims made:

"Africa is the most diverse continent on earth" to mean "A West African is closer genetically to a European than they are to other Africans" for instance.

Correct, sub saharans are more similar to sub saharans than europeans. Africa has the most diversity of all of continents.

they migrated more often between regions

Wrong, they spent a lot of time not migrating. Africa has a couple of very ancient and distinct genetic groupings, west africans, east africans and south africans with a lot of diversity within them. However, you don't see as much large scale intermixings or replacements suddenly appear like in europe or asia until the bantu migration. Instead population mixing happened at the peripheries of the two groupings territory. From DNA testing we can see a gradient between ancient east african foragers and south african foragers from ethiopia to SA distinct and unmixed at the poles but mixed in the middle in malawi and zanzibar island(Reich 222).

each group was isolated to their specific pocket of Africa for longer and that is how genetic variation develops over time

Correct, but he's too rslured to connect it back to what he said earlier about migration.

The San people are the first humans, myth.

Incorrect. The San are the oldest unmixed lineage as he says. He's too rslured to realized they're two different claims.

The real "first people" were black people, with dark skin, large noses etc. among other features which us Black people have and if we want to see what they may have looked like, we can look at the Hadzabe or Sandawe among the dozens of groups from East Africa.

This is a really complicated topic, but Hadza are decended from East African foragers, which split off from a shared ancestor of south african foragers whos decendants are the san and EA foragers. There is no telling what their shared ancestor looked like or if that shared ancestor is the first "real people". Not to mention thats a very contentious term, theres neanderthal(Reich 35) and denosivan dna(Reich 191) in various amounts amoungst different eurasian lineages and DNA evidence with 4 population tests that it was intermixing of eurasian migrants with indigenous peoples. By the standard definition of species the ability to carry fertile children the first "real person" would be much much older than the split between those two populations. Anatomically modern who is to say? But to say they're more similar to a lineage closer to a modern east african population discounts they could have features similar to populations mixed with even more ancient lineages like europeans, papuans, east asians and west africans(Reich 213) or less similar to their oldest unmixed decendant lineage the San is a very difficult to make claim.

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