Since I last blogged about the Knanaya Christians of Kerala my collaborator has gotten me more samples from this southern state. I decided to look at all the Knanaya (I’m nearly 20 samples now), the 5 Nasrani I have, and 2 Nairs and 2 Mappila.
I’m running some more detailed analyses, but I thought I would pass on what I’ve found out so far. You can see in the PCA and in the unsupervised admixture plot to the right and the supervised plot to the left that Knanaya are enriched for West Asian ancestry. I included Yemeni Jews since they are one end of the “pole.” The Middle Eastern ancestry of the Knanaya are likely to be Semitic, not Iran. These results confirm it.
The Nasrani samples I have also show this pattern. But it is attenuated. Finally, the two Mappila, Muslims from Kerala, do not show a shift at all. The two Nair are in the same place as South Indian Brahmins. This is likely the consequence of sambandam.
All that being said, I feel that the Kerala populations as a whole are often “west-shifted.” Why? My hunch is that the seaborn trade with the “west” was long-standing and pretty extensive.
Finally, I’m always struck by how some North Indian groups have more “steppe” ancestry than Iranians.