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Abstract:
India is home to thousands of ethno-linguistically distinct groups, many maintaining strong self-
identities that derive from oral traditions and histories. However, these traditions and histories are
only partially documented and are in danger of being lost over time. More recently, genetic studies
have established the existence of ancestry gradients derived from both western and eastern
Eurasia as well as evidence of practices such as endogamy and consanguinity, revealing
complexity in the regional population structure with consequences for the health landscape of
local populations. Despite the increase in genome-wide data from India, there is still sparse
sampling across finer-scale geographic regions leading to gaps in our understanding of how and
when present-day genetic structure came into existence. To address the gaps in genetic and oral
histories, we analyzed whole-genome sequences of 70 individuals from Southwest India
identifying as Bunt, Kodava, and Nair—populations that share unique oral histories and origin
narratives—and 78 recent immigrants to the United States with Kodava ancestry as part of a
community-led initiative. We additionally generated genome-wide data from 10 individuals self-
identifying as Kapla, a population from the same region that is socio-culturally different to the
other three study populations. We supplemented existing but limited anthropological records on
these populations with oral history accounts narrated by community members and non-member
contacts during sampling and subsequent community engagement. Overall, we find that
components of genetic ancestry are relatively homogeneous among the Bunt, Kodava, and Nair
populations and comparable to neighboring populations in India, which motivates further
investigation of non-local origin narratives referenced in their oral histories. A notable exception
is the Kapla population, with a higher proportion of ancestry represented in the Onge from the
Andaman Islands, similar to several South Indian tribal populations. Utilizing haplotype-based
methods, we find latent genetic structure across South India, including the sampled populations
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was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
bioRxiv preprint doi: https://doi.org/10.1101/2022.07.06.498959; this version posted July 7, 2022. The copyright holder for this preprint (which
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from Southwest India, suggesting more recent population structure between geographically
proximal populations in the region. This study represents an attempt for community-engaged
anthropological and genetic investigations in India and presents results from both sources,
underscoring the need to recognize that oral and genetic histories should not be expected to
overlap. Ultimately, oral traditions and unique self-identities, such as those held close by some of
the study populations, warrant more community-driven anthropological investigations to better
understand how they originate and their relationship to genetic histories.
