ArainGang, has posted a pretty interesting map of various ancestry components in the subcontinent by population. It’s pretty good, especially for the south and west of the subcontinent. But, there is something weird going on in the northeast: a lot of these populations have “Ancestral Indian” (Andamanese) ancestry but hardly anything else East Asian. This seems wrong. In fact, the Khasi are on a cline to Bengalis. I ran a few analyses on samples with the Andamanese and I just don’t see that Global 25 is doing this right.
In the Global 25 model above the Khasi are 33% Ancient Indian, proxy for AASI, who are most closely related to the Andamanese. But you see in the analysis here the Khasi are along the India cline, but very shifted to the Han Chinese.
I ran a three-population test with a bunch of populations. You can see here that though the Andamanese are in the data set, the Khasi are best thought of as a mix of Han Chinese with an on-elite North Indian population.
|pop a||pop b||f3 stat||error||Z-score|
What does this mean? I don’t think it’s a big deal. If the population does not have East Asian ancestry to a great extent the plot by Araingang looks fine. But, obviously, Global 25 has some kinks that people need to consider. This is important because people often come to me with Global 25 as if it’s authoritative. It’s not. It’s just another way to reduce genetic variation in a human consumable fashion.