Who was here first? That question is at the heart of the prevailing political narrative in India that looks to define the country as the true home of only one particular type of citizen.

But in a new book, Early Indians, published by Juggernaut Books, the writer Tony Joseph shows how waves of migration created the Indian population as we know it today. Using the latest discoveries in population genetics, he traces the fascinating story of how Indians came to be, and clears up the politicised misconceptions that have been fueling communalism and religious conflict in India for decades.

In an email interview with Quartz, Joseph explained the challenges of analysing this prehistory in the current political climate, and why it’s important for schools to start teaching the story of the early Indians.

Edited excerpts:

Your book argues that today’s tribals should be seen as the foundational population of India. Can you explain that further for our readers?

The ancestry of the First Indians, that is those who arrived in India around 65,000 years ago, accounts for 50 to 65% of the ancestry of all Indian population groups, no matter where in the caste hierarchy they stand, what language they speak, or which region they inhabit. Many tribal populations, in a relative sense, carry this ancestry to a higher level than other Indians, and to that extent, they can be seen as the foundational population of India. But the more important point is this: The tribals share their ancestry with the rest of the Indian population and so they are closely and intimately related to “us.” Therefore, there is zero basis to continue to see them as different from the rest of the Indians in any way. To those who ask, “where did the First Indians go,” or “where are they today,” the answer is: look in the mirror!

Given that the idea of there once being a pure, original type of Indian is being increasingly used to fuel a political narrative, what is it that you want readers to take away from your book?

“We are all kin. That is the message for readers to take away.”

That the Indian population was shaped by four, large prehistoric migrations. The first involved the Out of Africa (OoA) migrants who reached India about 65,000 years ago and whom my book calls First Indians. The second involved agriculturists from the Zagros region of Iran who arrived in northwestern India between 7000 and 3000 BCE, mixed with the First Indians and helped speed up the agricultural experiments that were already beginning in the subcontinent. The result was that farming spread like wildfire across the northwestern region, especially of barley and wheat, thus laying the foundation for the Harappan Civilisation that lasted in its mature phase from 2600 BCE to 1900 BCE. The third major migration was from southeast Asia around 2000 BCE, when farming-related population expansions originally starting from the Chinese heartland overran southeast Asia and then reached India, bringing the Austroasiatic family of languages, such as Mundari and Khasi which are today spoken in the eastern and central parts of the country. The last, or the fourth, major migration happened between 2000 and 1000 BCE and this brought Central Asian pastoralists, who spoke Indo-European languages and called themselves “Aryans” to India. There was large-scale mixing between these different population groups between around 2000 and 100 CE. Around 100 BCE there seems to have been a change in the reigning political ideology and, as a result, mixing between different population groups stopped, and this is probably linked to the beginning of the caste system. So the central message of the book is that we are all descendants of migrants who mixed and mingled with each other for millennia, before the caste system fell into place. We are all kin. That is the message for readers to take away.

Can you tell us more about how technology has helped the process of uncovering such “origins”?

What has really changed the nature of the discoveries is ancient DNA, or aDNA. Earlier, population genetics studies could discover affinities between population groups, but they could not conclusively settle the issue of the direction of movement of people. They could make intelligent deductions that most scientists would agree with, but they could not settle the issue. But when you have access to aDNA from the same location at different time periods, or when you have access to aDNA from different adjacent sites from the same period, you can see on the ground who moved when and where. This has radically changed our understanding of population movements, culture change, and prehistory in general. When we put this new aDNA findings together with the latest findings of archaeology, linguistics, epigraphy, and philology, we get a robust understanding of prehistory—as I said, not just in India, but across the world. The prehistory of Europe, East Asia, and the Americas are also being rewritten as we speak.

What are some of the difficulties in tracing this story in a place like India?

Some parts of our prehistory are part of current political conversation, and that makes it very difficult for scientists to do their work with the kind of openness and frankness that is otherwise common in scientific disciplines. This applies mostly to the topic of “Aryan” migration. There is an extraordinary level of sensitivity that is attached to this topic that is unique and surprising. As I had written elsewhere, “You could stand in the middle of a crowded market in Hyderabad, Bengaluru, Chennai, or Kochi and say that the common ancestor of the languages Kannada, Telugu, Tamil, and Malayalam was brought to India by migrants from west Asia some 8,000 years ago, and no one is likely to care or protest. You could stand in the middle of Jharkhand and say that Austroasiatic languages such as Mundari, Santali, and Ho came to India from southeast Asia around 4000 years ago, and no one is likely to raise a finger against you. You can stand anywhere in India and say that the earliest Indians were Out of Africa migrants who reached south Asia some 65,000 years ago and no one would really mind.

But if you were to say that an early version of Sanskrit was brought to India from central Asia by pastoralists who called themselves ‘Aryans,’ expect the skies to open and pour condemnation down on you.

“Sometimes, one must point out, it is not question of bias, but a belief that truth might have harmful side-effects…”

The reason for this special touchiness, I think, is the assumption that the ‘Aryan,’ or Vedic or Sanskrit culture is synonymous with Indian culture and to suggest that it may have come from elsewhere is to suggest that Indian culture is foreign! But this is a ridiculous assumption on various counts. First of all, Indian culture is not synonymous with, or identical to, ‘Aryan’ or ‘Sanskrit’ or ‘Vedic’ culture. ‘Aryan’ culture was an important stream that contributed to creating the unique Indian civilisation as we know it today, but by no means was it the only one. There are other streams that have contributed equally to making Indian civilisation what it is, such as the Harappan Civilisation that preceded the ‘Aryans.’ Second, to say that Indo-European languages reached India at a particular historical juncture is not the same as suggesting that the ‘Vedas’ or ‘Sanskrit’ or the ‘Aryan’ culture was imported flat-packed and then reassembled here. ‘Aryan’ culture was most likely the result of interaction, adoption and adaptation among those who brought Indo-European languages to India and those who were already well-settled inhabitants of the region.”

So to answer your question, this special sensitivity has come in the way of open and frank scientific discussion and has also led, at times, to personal preferences playing a part in how scientific findings are interpreted. Sometimes, one must point out, it is not a question of bias, but a belief that truth might have harmful side-effects and, therefore, needs to be treated cautiously.

You also mention in the book that schools should start teaching Indian history from long before the Harappan Civilisation, which is the usual starting point. Why is that important?

Where you begin your history is important because it often portrays biases about who or what part of your history you think is important and who or what part is not. It would be wrong for American or Australian history to begin with the arrival of the Europeans on those continents, because there is a long history that precedes them. It would also be ridiculous for Pakistan to consider its history as beginning only after the Islamic invasions began. Such choices make for a poor understanding of their own heritage. In our case, the fact that the ancestry of the First Indians is dominant makes it doubly important that we begin our history with the arrival of the First Indians around 65,000 years ago. Until now, we didn’t have a clear enough understanding of our own prehistory, so there was justification for ignoring much of it. But this is no longer the case. Our understanding of prehistory has expanded rapidly in recent years, and textbooks need to reflect that.

Are the genetic studies conducted so far conclusive or still in progress?

The interesting thing about aDNA-based discoveries around the earth is that it is like solving a jigsaw puzzle—the different pieces of evidence have to fit together well, geographically, because these are all interconnected. So as more and more aDNA-based studies are done the world over, the robustness of these findings increase exponentially, and it becomes more and more difficult to imagine any sudden and singular discovery upturning the entire jigsaw. What I expect will happen is that newer discoveries will unravel more of the story in greater detail and granularity. For example, in India, we do not know much about what happened in the millennium after all the four migrations happened. At that time, India was probably going through its most tumultuous and momentous period ever—a civilisation had just fallen apart, people who created that civilisation were migrating to the east and south, new migrants were coming in both from the west and the east, bringing new languages, new cultural practices, and new technologies, and there was mixing between populations on a scale that was unprecedented. New discoveries, not just in population genetics, but in other disciplines as well, should throw more light on how this process unfolded. The problems that population genetics has solved in recent years should provide a solid ground on which other discoveries can build.