By Veteran Brigadier Azad Sameer
Up until modern times we theorised and formulated ancient history through archeology and historical linguistics. Archeologists dug up ancient sites and by the study of artifacts and other evidence from these sites formulated their inferences. In historical linguistics, scholars use related languages as archeological sites, and they dig through layers of vocabulary and grammar to uncover the past. This multi-disciplinary field has now entered the science of Population Genetics and Paleo- Genomics which help solve the jigsaw puzzle with a lot more clarity.
Back in school a half century ago we learnt about the Aryan and Dravidian ancient history of India. How has science changed this old narrative if at all? The Aryan-Dravidian narrative has shifted from a story of conquest and pure races to a much more complex story of deep-time mixing. The modern Indian population is often described as a subcontinent-sized mystery. However, through the lens of paleo-genomics—the study of ancient DNA—we can now reconstruct the history of India not just through ruins and texts, but through the very cells of its people. Modern population genetics has replaced the old labels with three primary ancestral building blocks or three pillars that exist in almost every Indian today, regardless of whether they speak a Dravidian or Indo-Aryan language and regardless of from where they hail in the subcontinent or their religion or caste. So, let’s delve into each of these three building blocks as almost every Indian has inherited genes from all three blocks to a lesser or greater extent.
The Foundation: The Out of Africa Pioneer Group
The story begins with the First Indians, also probably the first Homo sapiens around 50,000 to 65,000 years ago, a small band of Homo sapiens migrated out of Africa, likely crossing the Bab-el-Mandeb strait and via the Arabian Peninsula, following the Southern Coastal Route into India. The migration Size was relatively small and perhaps covered a thousand plus years. Genetic modeling by Narasimhan et al. (2019)[i] suggests a significant bottleneck. While thousands may have left Africa, only a few hundred to a few thousand successfully founded the lineage that would populate the whole of South Asia. These pioneers are referred to as Ancient Ancestral South Indians (AASI) and should be considered as the indigenous people of India as they are known to be the first Homo sapiens who arrived in the subcontinent more than 50000 years ago. It is not conclusively known if humans lived in the subcontinent before the AASI, but if they did, they have left no genetic signature in the population of today. Currently, no pure AASI population exists on the mainland; they are a ghost population whose DNA is found mixed into nearly every person in India. The closest living relatives to this ancient lineage are the Andamanese hunter-gatherers (Onge and Jarawa).
It is also very likely that archaic Humans (other than Sapiens) lived in the subcontinent prior to the arrival of this group out of Africa and possibly coexisted with them for many centuries. Indians today have about 2% DNA of these archaic humans (Neanderthal and Denisovan), the highest for any population outside Africa
The Neolithic Revolution and the Indus Valley Civilisation (IVC)
Between 10,000 and 7,000 years ago, a new genetic stream entered from the west—people related to the early farmers of the Zagros Mountains (Iran). These Iranian-related migrants did not replace the AASI; they merged with them. This Indus Periphery mixture created the genetic basis for the Indus Valley Civilisation (IVC). A pivotal study by Shinde et al. (2019)[ii] sequenced the DNA of a 4500-year-old female skeleton from Rakhi Garhi. The results were revolutionary: she had zero Steppe ancestry. This proved that the great cities of Harappa and Mohenjo-Daro were built by a population that was a mix of AASI and Iranian-related ancestry, before the arrival of Central Asian groups. Most scholars now believe that the Indus Valley people spoke a proto-Dravidian language (their script is sadly still not deciphered)
The Steppe Migration and the ANI/ASI Split
Around 2000 BCE to 1500 BCE, as the IVC began to decline (likely due to climate change and drying rivers), a third major group arrived: Steppe Pastoralists from the Eurasian grasslands (modern-day Russia/Kazakhstan or the Yamnaya culture). These migrants brought Indo-European languages and early Vedic culture. Their arrival triggered a massive demographic shift:
The North: Steppe migrants mixed with the IVC people in the North, creating the Ancestral North Indians (ANI). This is the foundation on which the Vedic civilization was built. The early Vedas written in Sanskrit, have quite a few Dravidian loan words. This possibly shows the affinity/ descend of the Vedic people to the IVC people, who scholars believe spoke some kind of proto-Dravidian language.
The South: IVC people who moved South, further mixing with local AASI hunter-gatherers, formed the Ancestral South Indians (ASI). They formed the base for the Dravidian culture and civilization.
The Melting Pot
These two were not watertight, separate and pure Aryan/Dravidian entities. For the next two millennia or so (from 2000 BCE to 0 CE), they mixed freely with gene flows taking place throughout the subcontinent. It was clearly a no caste bar situation throughout the length and breadth of the subcontinent. Reich et al. (2009)[iii] demonstrated that most modern Indians are a cline (a sliding scale) between these two groups. A person in Kashmir might have 50-60% ANI ancestry, while a person in Tamil Nadu might have 20-30% ANI ancestry, but almost everyone has both North and South Indian ancestry. Population Genetics has thus conclusively proved that the whole of India has a by and large a common genetic heritage. Pure Aryan/ Dravidian heritage in India is something of a myth. There is a certain oneness in the common ancient heritage of every Indian.
The Endogamy Freeze (2,000 Years Ago)
Perhaps the most Indian aspect of this genetic story is not the mixing, but when the mixing stopped. Moorjani et al. (2013)[iv] discovered that around 1,900 years ago, genetic data shows a sudden freezing of the gene pool. This aligns with the late Gupta period when the Manusmriti was composed, and the social structures of the Caste System became rigid. From this point on, people began marrying only within their specific sub-castes (Jatis). This created thousands of distinct genetic groups. India is therefore not one large population; it is a collection of thousands of small, endogamous populations living side-by-side and interestingly all having a common heritage. This rigid monogamy froze the genetic proportions in place, which is why genetically and otherwise we still see distinct regional and caste differences today despite the shared ancient roots. This gene flow freeze that prevails till today gave rise to several deleterious effects socially, economically and biologically. That calls for a separate discussion altogether.
Religion, Gene Flow, and Regional Nuance
Modern socio-political identities often suggest deep divides, but the DNA tells a story of shared heritage. Study after study on religious groups, including Reich (2018), has shown that Indian Muslims and Christians are genetically indistinguishable from the Hindu castes of their specific region. For example, a Kerala Syrian Christian shares the same ancestral proportions as a Kerala Namboothiri or Nair. The closest genetic kin of a Kashmiri Muslim is the Kashmiri Pandit. Almost identical heritage. For most of us it would be somewhat disconcerting that a Punjabi Hindu or Sikh is genetically closer to a Punjabi Pakistani Muslim, than a Hindu from say Tamilnadu. Gene flows don’t recognize borders and genetically the concept of Akhand Bharat is very much a valid concept
There is an ethnic group called Brahui who now predominantly live in the mountains of Balochistan with much smaller populations in Iran, Afghanistan, and Gujarat and Rajasthan. Genetically they are predominantly ANI stock but the Brahui language that they speak today is essentially a Dravidian language strongly suggesting a IVC lineage.
Gene Flow from the East
In Northeast India and among Munda-speaking tribes in Central India, there is a significant fourth stream of DNA besides the three discussed above. This comes from Austroasiatic (AAA) and Tibeto-Burman migrations from Southeast Asia and East Asia roughly 3,000 to 4,000 years ago.
Summary Table: The Layers of Indian Ancestry
| LAYER | GROUP | ARRIVAL | FORMATION/IMPACT |
| 1 | AASI(FIRST INDIANS) | 50000 + years ago | Foundational DNA of all Indians |
| 2 | Iranian related farmers | 10000-70000 years ago | Mixed with AASI to build the Indus Valley civilisation |
| 3 | Steppe Pastoralists | 2000-1500 BCE | Introduced Indo European languages; formed the ANI |
| 4 | East Asian/ Austroasiatic | 2000-1000 BCE |
Out of India Theory (OIT)
Also known as Indigenous Aryanism, the Out of India Theory is the hypothesis that Indo European language family and speakers originated within the Indian subcontinent and migrated outward to Europe and Central Asia, rather than entering India from outside. This hypothesis stands in direct opposition to the mainstream Aryan migration Theory. In the academic world of genetics, archeology and linguistics the OIT is largely considered discredited. However, it remains a popular and culturally significant idea. In some sense the theory is valid in that the Indian Civilisation has immense indigenous continuity even before the arrival of the Steppe Pastoralists.
Old School Narrative and Modern Genetic Reality
The old schoolbooks often portrayed the Aryans/Dravidians as two separate, non-overlapping groups. Genetics shows they are more like a spectrum. According to the old school narrative Dravidians were Indigenous people pushed South by invaders. According to modern genetics this group (often called Ancestral South Indians or ASI) formed when the Indus Valley people migrated South and mixed further with local hunter-gatherers (AASI the original out of Africa indigenous people). The old school narrative describes Aryans as a foreign race that conquered the North. According to modern genetics this group is a mixture of Steppe Pastoralists and the existing Indus Valley population. This group (called Ancestral North Indians or ANI) is genetically closer to West Eurasians but still contains significant indigenous Indian DNA.
Key Changes in Knowledge
The Invasion is now a Migration: The violent Aryan Invasion Theory has been largely debunked. Genetic evidence suggests a slow, multi-century migration of Steppe people who intermarried with local populations.
Everyone is mixed. There is no pure Aryan or Dravidian. Nearly every Indian—from a Kashmiri Pandit to a Tamil Brahmin to a tribal member in Kerala—carries a combination of these three ancestral lines. The difference is only in the proportions (e.g., higher Steppe ancestry in the North/Upper Castes; higher AASI ancestry in the South/Tribal groups).
So, in a nutshell we can summarize that the current Indian population is not a monolith but a mosaic of varying shades, a picture largely accepted by the Centre for Cell and Molecular Biology (CCMB), Hyderabad, a premier research institution that has carried out groundbreaking research in this field.
[i] Narasimhan, V. M., et al. (2019). The formation of human populations in South and Central Asia. Science. (Detailed the three-way mix of AASI, Iranian-farmers, and Steppe).
[ii] Shinde, V., et al. (2019). An Ancient Harappan Genome Lacks Ancestry from Steppe Pastoralists or Iranian Farmers. Cell. (The definitive study on the Indus Valley genome).
[iii] Reich, David (2018). Who We Are and How We Got Here. (A comprehensive overview of ancient DNA findings in India and globally).
[iv] Moorjani, P., et al. (2013). Genetic Evidence for Recent Population Mixture in India. American Journal of Human Genetics. (Identified the shift to endogamy 1,900 years ago).
REJINCES 