DNA Reveals Unknown Ancient Migration Into India

For ten years, Genographic Project scientists have explored and explained how patterns in our DNA show evidence of migration and expansion routes of our ancient ancestors across the globe. DNA has shown that genetically modern humans arose in Africa some 150,000 years ago, and around 60,000 years ago left Africa and went east into Asia, north into Europe, and south into Australia. But new research from Genographic Project scientists in India shows that eventually some of them also moved back west, and brought their language with them.

Genographic Project scientists Drs. Ramasamy Pitchappan and GaneshPrasad ArunKumar from Tamil Nadu, India, analyzed the Y-chromosome (paternally-inherited) DNA from more than 10,000 men from southern Asia. The findings, published in the Journal of Systematics and Evolution, showed that in the last 8,000 years humans expanded west from Southeast Asia back to India.

A Lao farmer paddles along a golden river at sunset. (Photo by W.E. Garrett)

This previously undetected migration is evident from the frequency and diversity of a specific genetic clan, or haplogroup, in that part of the world. The Genographic scientists found a much higher frequency of haplogroup O2a1 in their research than expected. “Since O2a1 is accepted as the founding lineage of Austro-Asiatic languages (a group of related languages from Southeast Asia), the origin and spread of this lineage gives clues on the history of these speakers and the region. Our study shows a clear decrease in age and diversity of haplogorup O2a1 from Laos to East India, suggesting an east to west spread out of Southeast Asia,” explains Dr. ArunKumar about his findings.

Dr. ArunKumar working in the field
Dr. G. ArunKumar collects samples in the field in eastern India. (Photo courtesy of G. ArunKumar)

But why did they focus on just one haplogroup, when there are hundreds of distinct haplogroups in Asia? “The Y chromosomal haplogroup O2a1 accounts for almost 15 percent of Indian male lineages and 58 percent of male lineages from Southeast Asia, and the distribution of this haplogroup matches the distribution of Austro-Asiatic languages (i.e. Vietnamese, Cambodian, Munda, and Nicobarese), and some of these Austro-Asiatic speaking populations are 100-percent haplogroup O2a1,” adds Dr. ArunKumar. “Thus understanding the distribution of O2a1 sheds light on the origin and movement of people in that part of the world.”

Haplogroup O2a1
Around the darkest red spot in southern Asia in the map above, two small arrows indicate the westward movement of people of haplogroup O2a1 from Laos back into India. (Image courtesy The Genographic Project)

Previous Genographic Project studies have also shown strong correlations between language and frequency of a certain haplogroup. Examples include the relationship between Indo-European languages and paternal haplogroup R1, and Austronesian languages and mitochondrial DNA (maternal) haplogroup B4. In each case, language similarities paralleled genetic similarities.

So, does this mean that the language you speak is ingrained in your DNA? Well no, but even though language is learned (nurture) and DNA is inherited (nature), the two are undoubtedly interconnected and, as we have shown, correlated.

Learn more about this and other Genographic Project research and what haplogroups our scientists are currently studying at genographic.com.

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Meet the Author
Dr. Miguel Vilar is the Science Manager for National Geographic's Genographic Project. Miguel is also a molecular anthropologist and a science writer. His fieldwork has taken him to remote places throughout the South Pacific, East Africa, Mesoamerica, and the Caribbean. In the laboratory he researches the modern genetic diversity of human populations from Melanesia, Micronesia, North and Central America, and the Caribbean. Miguel has published in several anthropology and genetics journals, as well as popular science magazines.