The Toda People Of India Are Genetically Distinctive

The Toda people of South Asia live in mountains at the Southernmost tip of the Deccan Peninsula of India. They are right about where one would expect a population with very low levels of steppe ancestry in India to be located. And, their traditional non-Hindu religion makes sense in a place with low levels of steppe ancestry.

But their low levels of ancestral South Indian ancestry relative to Harappan ancestry is a far more mysterious puzzle.  

While these people may have spoken a Harappan language, the hypothesis that "Neolithic people of the Tamil country spoke a Harappan language", generally, seems unlikely.

Perhaps it was an ancient Harappan trading colony, something documented in other liminal areas in Southwest India, that lost contact with its homeland?

A new paper on Southwest Indian genetics highlights the Toda sample from Genomes Asia. People . . . have asserted this small southern tribe may have the most “Indus Valley Civilization” ancestry in the subcontinent. This is perhaps an exaggeration, but, looking at the admixture plots the Toda clearly have hardly any steppe ancestry, but a lot less “ASI” [ancestral South Indian] ancestry than their tribal neighbors, with the balance being something like the IVC ancestry.

From Razib Khan at Brown Pundits. 

The abstract of the paper linked above states:

India is home to thousands of ethno-linguistically distinct groups, many maintaining strong selfidentities 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 selfidentifying 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 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.

Who are the Toda people?

The Toda people are a Dravidian ethnic group who live in the Nilgiri Mountains of the Indian state of Tamil Nadu. 

Before the 18th century and British colonisation, the Toda coexisted locally with other ethnic communities, including the Kota, Badaga and Kurumba, in a loose caste-like society, in which the Toda were the top ranking. During the 20th century, the Toda population has hovered in the range 700 to 900. 

Although an insignificant fraction of the large population of India, since the early 19th century the Toda have attracted "a most disproportionate amount of attention because of their ethnological aberrancy" and "their unlikeness to their neighbours in appearance, manners, and customs". . . . 

The Toda traditionally live in settlements called mund, consisting of three to seven small thatched houses, constructed in the shape of half-barrels and located across the slopes of the pasture, on which they keep domestic buffalo. Their economy was pastoral, based on the buffalo, whose dairy products they traded with neighbouring peoples of the Nilgiri Hills. 

Toda religion features the sacred buffalo; consequently, rituals are performed for all dairy activities as well as for the ordination of dairymen-priests. The religious and funerary rites provide the social context in which complex poetic songs about the cult of the buffalo are composed and chanted.

Fraternal polyandry in traditional Toda society was fairly common; however, this practice has now been totally abandoned, as has female infanticide. 

During the last quarter of the 20th century, some Toda pasture land was lost due to outsiders using it for agriculture or afforestation by the State Government of Tamil Nadu. This has threatened to undermine Toda culture by greatly diminishing the buffalo herds. 

Since the early 21st century, Toda society and culture have been the focus of an international effort at culturally sensitive environmental restoration. The Toda lands are now a part of The Nilgiri Biosphere Reserve, a UNESCO-designated International Biosphere Reserve; their territory is declared UNESCO World Heritage Site. . . . 

Prehistory

Archaeological evidence points to this area being one of the longest continuous habitations in the Indian peninsula. 

In Attirampakkam near Chennai, archaeologists from the Sharma Centre for Heritage Education excavated ancient stone tools which suggest that a humanlike population existed in the Tamil Nadu region somewhere around 1,000 years before homo sapiens arrived from Africa. 

A Neolithic stone celt (a hand-held axe) with the Indus script on it was discovered at Sembian-Kandiyur near Mayiladuthurai in Tamil Nadu. According to epigraphist Iravatham Mahadevan, this was the first datable artefact bearing the Indus script to be found in Tamil Nadu. According to Mahadevan, the find was evidence of the use of the Harappan language, and therefore that the "Neolithic people of the Tamil country spoke a Harappan language". The date of the celt was estimated at between 1500 BCE and 2000 BCE. In Adichanallur, 24 km (15 mi) from Tirunelveli, archaeologists from the Archaeological Survey of India (ASI) unearthed 169 clay urns containing human skulls, skeletons, bones, husks, grains of rice, charred rice, and celts of the Neolithic period, 3,800 years ago. The ASI archaeologists have proposed that the script used at that site, Tamil Brahmi, is "very rudimentary" and date it somewhere between the 5th century BCE and 3rd century BCE. About 60 per cent of the total epigraphical inscriptions found by the ASI in India are from Tamil Nadu, and most of these are in the Tamil language. In Keezhadi near Madurai, excavations have revealed a large urban settlement dating to the 6th century BCE, during the time of urbanisation in the Gangetic plain. During this dig, some potsherds were uncovered with a script similar to Indus script, leading some to conclude it was a transition between the Indus Valley script and Tamil Brahmi script used in the Sangam period.