Genetics has shown that there was movement between India and Europe centuries ago. But science can spread no light on the direction of this migration, whether the migrants were Aryans, and what their culture was like.

There has been considerable discussion on the movements of the ‘Aryans’ and their contribution to the development of the Hindu society. According to the Aryan Invasion theory, the Aryans are a race of people who conquered India circa 2000 BC and subjugated the indigenous people into slavery, laying the foundation for the Hindu caste system. On the other hand, the Aryan migration theory suggests that instead of a military conflict, the Aryans peacefully migrated and assimilated with the indigenous Indians, contributing to their cultural development. Both theories acknowledge the Aryans to be Sanskrit speakers who authored the Vedas and have extensively employed two scientific rationales – linguistic and archaeological – as evidence of their authenticity. More recently, the use of genetics to identify the origin of the Aryans is being pursued.

Since genes are inherited from one’s parents, they can be extremely useful in tracing ancestry. Genetic testing is routinely used to resolve paternity suits; but what can genetics tell us about our grandparents from 4000 years ago? Geneticists study two forms of DNA: the Y DNA which is passed from father to son, and the mitochondrial DNA, which is passed from mother to child. Across generations, these forms of DNA undergo slight changes – these changes, known as mutation, then act as markers for all future descendants. Thus, if you and an American have the same characteristic mutation in the mitochondrial DNA, chances are you share a common ancestor.

Geneticists have identified a few key mutations that they now use to trace ancestry. Based on these, multiple studies have shown genetic similarity between a subset of the Indian population and European populations. To review them all will be beyond the scope of this article; I will however talk about the most recent study that has rejuvenated the Aryan debate in print and social media. A considerable amount has already been written rebutting (here, here, here and here) the article and suppositions (here, here and here) based on it. Instead of belaboring on those points, I am only going to talk about how the violation of a basic scientific principle undermines the validity of the study’s findings.

In this study, Silva et al use a specific Y chromosome mutation lineage (R1a1a) to inform on migration. The authors show the presence of this lineage in a subset of populations in India and Europe. They presume the authenticity of the Aryan migration theory and then superimpose their data to the timeline of the proposed migration. Based on this, a conclusion is made that there was a migration of people in 2000 BC from Central Asia into India. However, the study ignores an important control group in its methodology; controls are necessary markers to maintain the integrity of the experiment. In this case the critical control to validate the conclusion would have been to test populations, otherwise considered as indigenous Indians, for the absence of the lineage mutation. The presence of the mutation in this population would have precluded the conclusion that this lineage originated outside India. The complete absence of this population, the Indian tribal population, in the tested dataset dents the legitimacy of its findings. In fact, a previous study has demonstrated the presence of another related lineage, R1a amongst Indian tribal populations, other caste populations and Europeans.

Careful scrutiny of a number of such studies reveals that in most cases, geneticists do not testify to the Aryan migration theory. In fact, most agree that the genetic diversity in India is too complex to be explained by a single migration event. What is more likely is repeated migration across the subcontinent’s history bringing in admixtures of various ancestries resulting in the current genetic pool. So how do we associate one of these many migrations with the influx of the Aryans?

Genetic studies do confirm a migration event to occur at 2000-1500 BC, the proposed timeline of the Aryan migration. However, to deduce that this ancestor is the “Aryan” everyone is looking for, he would have to fulfill the following conditions:

Migrate from the West.

Author the Vedas (representative of their being Sanskrit speakers).

Lay the foundation of Hinduism (the structured caste system).

Can genetics inform on any of these conditions? The dating of a common ancestor circa 2000 BC suggests that the ancestor moved between the Indian sub-continent and Europe. Even if we take the studies at face value, none of them can conclusively identify the direction of the migration. To establish direction, we have to turn to other lines of evidence, such as archaeological or linguistic. However, neither of these lines of study have provided convincing proof that there was a migration into India. For genetics to establish direction, we will have to identify the oldest precursor lineage and trace subsequent mutations in it. The problem here is of negative data; how will we ascertain that we will never find a lineage older than ones we have? Since it is currently difficult to derive genetic data from remains that old (if even found), this approach at best can only provide circumstantial evidence.

Further, genetics cannot tell if the Aryans authored the Vedas or founded the Hindu caste system. At best, a link between the two can be implied if the writing of the Vedas and migration of Aryans happened concomitantly. However, we don’t have any definite time line for the establishment of the caste system, neither is the purported period of 1500 BC for the writing of the Rig Veda universally accepted. This date may at best a simplistic conjecture for what is a very complex piece of the Indian and global literary history. In the face of little evidence, the deduction that specifically the invaders of 2000 BC wrote the Vedas is a case of speculation and genetics cannot be used to bolster this claim.

So then can genetics be ever able to prove who are the Aryans? Companies such as 23andMe offer the tracing of ancestry through genetic testing – but for that they compare sample DNA to other people. For example, to study if someone has Jewish ancestry, their DNA would be compared to known Jews. But in the case of the Aryan genetic make up, we don’t know exactly who the Aryans were or who their descendants now might be. Is it enough for some Indians and Europeans to have similar genes to automatically tag them as the Aryans? Is it acceptable to believe that a subset of the current population was responsible for the cultural development of Hinduism? Or could it be possible that the Aryans were really just a heterogeneous group of people who lived in the Aryavarta as suggested in the later Manusmriti? Genetics can only be used to trace people, not a culture.

Finally, in India we see a heterogeneous population which has seen repeated and well-documented invasions from the West. Any data we get from India’s current population is at best evidence that people have moved across the sub-continent throughout different time points. To automatically present this as proof that the Aryans came from outside India is fallacious. To further claim that they are superior, and provoke discordance between the different peoples of India is political mischief. Neither of these things is science.