Over the past few months I have been getting together some samples from people from Kerala, with a focus on Knanaya Christians. A subset of the broader St. Thomas Christian community, two things have jumped out in my analyses:
– they are quite endogamous
– they are shifted off the ‘India-cline’
More precisely, like Cochin and Mumbai Jews, they are often shifted toward Middle Eastern populations. This is relevant because the Knanaya believe themselves, like most St. Thomas Christians, descended in part from Jews or Christians from the Middle East.
All that being said, looking more deeply into the data I’m not quite as sure. One of the reasons is that Kerala may not be as “structured” as other parts of India. Some of this is well known. The Nair samples I have are shifted toward South Indian Brahmins, which is plausible in light of connections between Nairs and Brahmins. The Brahmin-adjacent Ambalavasi seem quite similar to Brahmins. These are not surprising. But, Kerala samples I have as a whole seem notably shifted on the India cline more toward the “north” than I would have expected. This could be due to gene flow from without and within Kerala, in a way that is not typical in other parts of the subcontinent.
I say this because even the Ezhava, who were basically what we’d call a Dalit community (no longer today), shows a shift.
Instead of talking, let me post some admixture plots (unsupervised):
Here is an admixturegraph (using the Narasimhan et al. right-populations):
I ran f3-stat. Here it is filtered of any z-scores that are > -2.