Will New Component In Ancient Indian Ancestry Throw Genomic Research Into South Asian History Wide Open?

By Bodhisattwa Maity

New Delhi: A new research paper, published on October 24, 2025, in the European Journal of Human Genetics by J J Sequeira, Swathy Krishna M, George van Driem, M S Mustak and Ranajit Das, may have widened the scope of research into South Asia’s population history.

The paper, called Novel 4400-year-old ancestral component in a tribe speaking a Dravidian language, not only indicates a sixth "ancestral population", ie., one more group of ancient settlers who arrived from outside and settled in the subcontinent, eventually contributing to the genetic makeup of South Asia's population — but also throws open the door for the discovery of many more such groups of ancient migrants, whose traces would likely be found in small, relatively isolated groups existing today.

The researchers have identified this sixth ancestral component in a small, vulnerable tribe called the Koragas, who are found mainly in the coastal belt along Karnataka and Kerala. The researchers have named this Proto-Dravidian ancestry, a group that appears to have arrived around the time of the Indus Valley Civilisation (IVC).

Genetic studies over the past two decades had so far identified the five ancestral populations — the Ancient Ancestral South Indians (AASI) who migrated from Africa some 60-70,000 years ago and whose traces are found in some isolated Andaman tribes; the Neolithic Iranian (Zagros) agriculturists who arrived around 7-8,000 years ago when the IVC was already thriving, and mingled with them; the Steppe Pastoralists from the Central Eurasian steppes who were related to the IVC population and also mixed with them upon arrival some 3-4,000 years ago to give rise to what is called the Ancestral North Indian (ANI) population; the Ancestral Austro-Asiatic (AAA) from Southeast Asia whose traces are found in Central Indian tribes; and the Ancestral Tibeto-Burman (ATB) from East and Southeast Asia, whose traces are found in the populations of the Himalayan foothills, particularly in the Northeast.

The genetic research into the Koraga tribe was prompted by the widespread prevalence of specific genetic disorders in the population. It not only revealed a high prevalence of endogamy within the semi-isolated tribe that led to the prevalence of those genetic disorders, but, because of the endogamy and isolation, also left traces of what the paper calls the Proto-Dravidian signature.

Ranajit Das, an associate professor at Yenepoya University in Mangaluru, one of the contributing authors of the paper, said: "Our statistical modelling indicates that the ancestry contributing to Dravidian-speaking groups cannot be fully explained by the Neolithic Iranian Zagros farmer source alone."

"A distinct 'Proto-Dravidian' or Koraga-like ancestry fits the data better, when modelling Dravidian populations. This suggests that our population — ancestral to Dravidian — wasn't simply a downstream branch of the Zagros farmers, but a parallel and regionally-differentiated lineage that was present on the Iranian plateau–Indus Valley periphery, and arrived later to contribute to the Harappan cultural sphere. We therefore treat 'Proto-Dravidian' as a parallel, sister/neighbour ancestry to the Zagros farmer, a difference that persisted into the Chalcolithic/Harappan era, rather than being a later offshoot of it."

Das differentiated the modern Dravidians from the Proto-Dravidians as follows: "Proto-Dravidian are a specific ancestral component (Koraga-like) who we infer existed in the area between Iran and IVC around 4,400 years ago. They were associated with the early Dravidian-speaking populations, but weren't the same as the AASI, whose genetic traces are most significantly found in the Andamanese."

He added: "Modern Dravidian groups are populations formed by the admixture of Proto-Dravidians, Neolithic Zagros farmers, the AASI, and in many cases, the Steppe Pastoralists."

He further said, "Thus, the Proto-Dravidian genetic signature is one of the core ancestral ingredients, whereas modern Dravidians represent the outcome of multiple waves of admixture built on that ancestral base. In short, Proto-Dravidian is one ingredient, modern Dravidians are the final recipe."

So how do these findings change the overall understanding of India's genetic composition? Das replied, "Our study adds an important fourth ancestral layer (sixth, if you add the AAA and ATB) to the classic 'AASI + Zagros farmer + Steppe' model, by introducing a distinct Proto-Dravidian (Koraga-like) component. This helps resolve long-standing mismatches in modelling South Indian and Dravidian-speaking populations, particularly in the Harappan-adjacent zone. Most crucially, our findings open a new avenue to research into more, yet-to-be-identified ancestral components that India likely harbours."

"We have to understand that human ancestry isn't strictly additive or linear. Component A + Component B does not always produce a uniform Component C: It may yield different composite ancestries (C1, C2, D, etc.) depending on population history, direction of gene flow, drift, and sociocultural isolation," he said.

"This also means that the genetic landscape of ancient India was likely multi-layered and more complex than previously assumed. So, further ancient DNA sampling may reveal additional deep ancestries," Das said.

An interesting aside of this research that was thrown up by Das's explanations is that their genetic research is mapped on to linguistic patterns to identify and distinguish groups of ancient settlers in South Asia.

It prompted linguist Peggy Mohan, who has written two, widely-feted books — Kings, Merchants: The Story of India Through Its Languages, and Father Tongue, Motherland: The Birth of Languages in South Asia, in which she traces the origins of India's population using the diametrically opposite route — linguistics, to ask the question: "If the Dravidians and Proto-Dravidians are distinguished linguistically, how are they defined genetically?"

She also asked: "If they (Dravidians and Proto-Dravidians) were two distinct migrating groups, what were their languages before they arrived in the Indus Valley? Especially, as there seem to be no groups of Dravidians outside South Asia."

Clearly, there are interesting times ahead for our understanding of who we Indians are, and where we came from.

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