Rakhigarhi and Ancient DNA: What Genetics Can — and Cannot — Tell Us

Why Rakhigarhi matters

Rakhigarhi in Haryana is one of the largest known Harappan settlements and preserves occupations across major phases of the civilisation. Its cemetery supplied the first genome published from an individual securely associated with a Mature Harappan context.

A major technical achievement—and a sample of one

Heat, humidity and soil chemistry rapidly destroy ancient DNA in South Asia. Researchers screened remains from 61 individuals and repeatedly sampled one petrous bone and tooth before recovering enough authentic DNA for genome-wide analysis. That success is scientifically important, but the usable Rakhigarhi dataset represents one woman, labelled I6113.

What the genome contained

Statistical models placed I6113 on an ancestry gradient combining a deeply diverged Iranian-related lineage with ancestry related to ancient South Asian hunter-gatherers. Here ‘Iranian-related’ describes a genetic relationship, not proof that her recent ancestors migrated from modern Iran.

What was not detected

The study found no detectable Steppe-pastoralist ancestry in I6113 and little or no ancestry characteristic of sampled western Iranian or Anatolian farmers. The result is consistent with Steppe-related ancestry entering much of South Asia after the Mature Harappan period, but absence in one genome cannot establish absence in every Harappan community.

The Indus-periphery comparison

Eleven individuals buried at sites in present-day Iran and Turkmenistan carried related ancestry profiles and were treated as an Indus-periphery cline. Archaeological contact makes a connection plausible, but their burial places do not prove that every individual was born in an Indus city. The Rakhigarhi genome anchors the model within the civilisation itself.

Farming and ancestry

The Iranian-related component diverged from sampled Iranian farming populations before farming spread there. This weighs against a wholesale replacement of South Asian populations by the sampled western Iranian farmers. It does not by itself prove that every crop and farming practice was independently domesticated in South Asia; knowledge, plants, animals and smaller groups can move without mass migration.

Later South Asian population history

Large comparative datasets model many later South Asians as mixtures involving Indus-periphery-related ancestry and Steppe-related ancestry, with varying proportions and additional regional histories. These are statistical population models, not timeless biological races, and modern identities cannot be projected unchanged into the Bronze Age.

Genes do not reveal language

DNA records biological relationships, not the words a person spoke. No gene identifies Tamil, Sanskrit, Dravidian, Indo-Aryan or any other language. Linguistic hypotheses require linguistic and archaeological evidence, while the undeciphered Indus script prevents a direct language test.

Genes do not reveal caste, nation or religion

A genome cannot name an individual’s political affiliation, ritual beliefs, social rank or self-understanding. Modern national, caste and communal categories formed in different historical settings. Treating ancestry components as present-day communities turns probabilistic science into anachronism.

What would strengthen the evidence

More securely dated genomes from different sexes, cemeteries, regions and Harappan phases are essential. Isotopes, osteology, kinship, diet, burial context and artefacts should be analysed together. Replication and transparent sampling are especially important because preservation creates a severe and non-random bias.