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No, your split argument doesn't make the case you think it does. If groups A, B, and C were once groups A and B (and B split into B and C later), it's true that

No, your split argument doesn't make the case you think it does. If groups A, B, and C were once groups A and B (and B split into B and C later), it's true that B and C are likely closely related, but it doesn't mean A and B are more different than A and C. To put it another way, if we start with groups A and B, and then branch off B' from B, while B and B' are likely similar, that doesn't tell us anything about the relationship between A and B', and it doesn't imply that A and B' are closer than A and B.

snowwrestler 1y ago
The comment above is not making an argument, they are illustrating with an analogy. There’s no logical argument needed to prove the genetic diversity in Africa, it is an observed fact.
- reissbaker 1y ago
  I know that there is higher genetic diversity in Africa, and lower genetic diversity in non-African populations. That doesn't mean that there is greater difference between Africans and other Africans than between Africans and non-Africans; that only means there is greater difference between Africans and other Africans, than there is between non-Africans and other non-Africans. To put it another way: there is extremely low genetic diversity in peregrine falcons; housecats have much higher diversity. But the two most-different individuals, when taken from a sample that contains both housecats and peregrine falcons, will certainly be a housecat and a peregrine falcon. Despite falcons having lower genetic diversity, they are still more-different from a housecat than any given housecat is from another. Of course, humans are the same species, so it won't be as dramatic. But high genetic diversity amongst sub-Saharan African populations doesn't mean that sub-Saharan Africans are more different from each other than they are from East Asians (for example) — it only means they're more different from each other, than East Asians are from other East Asians. Pick any two people in China, and they're probably pretty genetically similar; pick any two people in sub-Saharan Africa, and they're probably pretty genetically different. That doesn't imply anything about how different the two Chinese people are from the two African people. Additionally, non-sub-Saharan populations typically have some non-Homo-Sapiens ancestry: Neanderthal and Denisovan, for East Asians, and just Neanderthal, for Europeans. While genetic diversity within those groups is low, it doesn't mean that genetic distance from any given sub-Saharan group is low.
bryanlarsen 1y ago
To expand the second part of my argument: If C' is only descended from C, but B' is descended from B and D and F and Z, then B' has increased its genetic diversity more than C' has.

snowwrestler 1y ago

The comment above is not making an argument, they are illustrating with an analogy. There’s no logical argument needed to prove the genetic diversity in Africa, it is an observed fact.

reissbaker 1y ago
I know that there is higher genetic diversity in Africa, and lower genetic diversity in non-African populations. That doesn't mean that there is greater difference between Africans and other Africans than between Africans and non-Africans; that only means there is greater difference between Africans and other Africans, than there is between non-Africans and other non-Africans. To put it another way: there is extremely low genetic diversity in peregrine falcons; housecats have much higher diversity. But the two most-different individuals, when taken from a sample that contains both housecats and peregrine falcons, will certainly be a housecat and a peregrine falcon. Despite falcons having lower genetic diversity, they are still more-different from a housecat than any given housecat is from another. Of course, humans are the same species, so it won't be as dramatic. But high genetic diversity amongst sub-Saharan African populations doesn't mean that sub-Saharan Africans are more different from each other than they are from East Asians (for example) — it only means they're more different from each other, than East Asians are from other East Asians. Pick any two people in China, and they're probably pretty genetically similar; pick any two people in sub-Saharan Africa, and they're probably pretty genetically different. That doesn't imply anything about how different the two Chinese people are from the two African people. Additionally, non-sub-Saharan populations typically have some non-Homo-Sapiens ancestry: Neanderthal and Denisovan, for East Asians, and just Neanderthal, for Europeans. While genetic diversity within those groups is low, it doesn't mean that genetic distance from any given sub-Saharan group is low.

bryanlarsen 1y ago

To expand the second part of my argument: If C' is only descended from C, but B' is descended from B and D and F and Z, then B' has increased its genetic diversity more than C' has.