Couple in traditional Kodava attire. Credits: Manshi Devaiah
India is home to many distinct groups, often living close together but with unique cultures and histories. One such group is the people of Coorg in Karnataka, also called Kodavas or Coorgs. They are an indigenous populace nestled in the Western Ghats in Kodagu district of Karnataka. Their culture, which includes a history of agriculture and martial traditions, and their social practices, like marrying outside their immediate family but within the larger Coorg community, set them apart from their neighbours. Their origins, however, have long been a puzzle. Are they ancient inhabitants of the region, or did they arrive from somewhere else, perhaps even linked to armies or groups from far-off lands like Greece or Central Asia, as some stories suggest?
Researchers from the University of Delhi and CSIR-Centre for Cellular and Molecular Biology (CCMB), Hyderabad, are studying the genetic code of the Kodava people to uncover their past. They collected DNA samples from 144 individuals of Kodava descent. Next, they looked at different types of genetic markers, which are fingerprints in our DNA that identify our ancestry.
Did You Know? Kodavas have distinctive dresses. The men wear wraparound robes called the Kupya (now only seen at ceremonial occasions), and the women with a distinctive style of wearing the sari. The men also have many distinctive practices such as carrying ceremonial knives, and martial war dances. |
The team looked at autosomal DNA, the genetic code inherited from both parents. They also used uniparental markers, like mitochondrial DNA (mtDNA) passed down from mothers and Y-chromosome DNA passed down only from fathers. By analysing these markers and comparing them to DNA from many other populations across India and the world, they could start piecing together the Coorg story.
They found that instead of one single, uniform group, the genetic data revealed that the present-day Coorg population comprises contributions from three distinct ancient groups, which the researchers labelled Coorg1, Coorg2, and Coorg3. Using computational and statistical methods, the researchers could see how these three genetic groups relate to each other and other populations. When they looked at the overall genetic picture using a technique called PCA (Principal Component Analysis), the Coorg individuals didn't just form one blob; they separated into three distinct clusters.
Coorg1 individuals tended to cluster closer to some tribal groups from Southern India, like the Palliyar, who are thought to have a lot of ancestry from the earliest people in South Asia called Ancient Ancestral South Indians(ASI). Coorg2 individuals were positioned somewhere in between, showing connections to groups with more ancestry from people who migrated from the north, called Ancestral North Indians (ANI), including some Indo-European caste groups. However, Coorg3 was unique; it didn't neatly cluster with any modern Eurasian or South Asian population that the scientists compared it to.
Further analysis using ADMIXTURE, which estimates the proportion of different ancestral components in a population, confirmed this. Coorg3 showed a distinct genetic component that wasn't found in other groups in the same way. Coorg2 looked like a mix, sharing ancestry with Indo-European-like groups and a bit of that unique Coorg3 component. Coorg1 was rich in the South Asian ancestry component, similar to tribal groups, and had very little of the unique Coorg3 component. Interestingly, all three Coorg groups shared some level of the Coorg3 component, suggesting it played a role in their overall history.
The scientists then used different methods to determine when these groups formed and mixed. They found evidence that Coorg1 is an older population that experienced a founder event around 40 generations ago, roughly 1000-1200 years ago, assuming about 25-30 years per generation. A founder event happens when a new population is started by a small number of individuals, leading to reduced genetic diversity and increased relatedness within the group. This explains why Coorg1 showed signs of long-term isolation and higher levels of relatedness compared to many other groups. Their analysis suggested Coorg1's ancestry could be traced back to a mix involving groups like the Palliyar and Mala, consistent with a link to ancient South Asian populations.
Coorg3 has a different, perhaps even earlier, history in the region. While it shows ancestry from the Indian cline (ANI-ASI mix), the data suggests a more recent pulse of admixture, around 23 generations ago (roughly 600-700 years ago), with a group related to present-day Sikh Jatt people from Northwest India, who represent an ANI-like population. Moreover, some analyses hinted at the possibility of an additional, as-yet-unknown ancient lineage contributing to Coorg3's genetic makeup. This group also showed signs of significant genetic drift, a phenomenon where random changes in gene frequencies become more pronounced in small or isolated populations. Still, unlike Coorg1, this drift seemed more related to long-term isolation than a single strong founder event.
The genetic story of Coorg2 appears to be the most recent chapter. The research indicates that Coorg2 was formed by the mixing of the older Coorg1 and Coorg3 groups around 11 generations ago (roughly 300-350 years ago). This mixing event likely contributed to the cultural and social similarities observed among Coorgs today, even though their genetic roots are distinct. The Y-chromosome DNA analysis added another layer, suggesting male-mediated migrations from Eurasian and Middle Eastern groups into the region over time, with these men eventually mixing with local South Asian women, whose maternal lineages (seen in mtDNA) are predominantly South Asian.
The research significantly improves our understanding of the history of the Kodavas by providing the first detailed genetic evidence of their population structure and history. Previous ideas about their origins were mainly based on stories or limited historical accounts, lacking scientific backing. This study uses genomic techniques to reveal a complex, multi-layered history that wasn't previously known. However, the study also highlights a limitation: the genetic findings, particularly the specific ancient origins and mixing events identified, don't directly match the oral histories or traditional beliefs about Coorg ancestry, such as links to Alexander's army. Additionally, the suggestion of an unknown ancient lineage in Coorg3 means there are still pieces of the puzzle missing, requiring further research.
Understanding the genetic history of groups like the Coorgs adds crucial detail to the broader picture of human migration and population dynamics in India and globally. It shows how isolation, migration, and mixing events shape the genetic diversity we see today. For the Coorg community itself, this research provides a scientific perspective on their unique identity, showing that their distinctiveness is rooted in a fascinating and complex genetic past. While it doesn't validate specific historical legends, it offers a new, evidence-based narrative about their deep ancestry, celebrating the diverse threads that weave together to form their unique genetic tapestry. It also underscores the importance of studying isolated populations, as they can hold unique clues about ancient human movements and the processes of genetic change
This article has been edited to correct a typo in the Did You Know section. The error is regretted.
This research article was written with the help of generative AI and edited by an editor at Research Matters.