The study of the human genome continues to yield new insights about our history. A new study on the variation seen across human populations has revealed an ancient migration from India to Australia 141 generations ago, one that hadn’t been on record.
It is accepted that human populations migrated out of Africa and subsequently colonized the world. Some previous studies have shown that a wave of migration (called the ‘southern route’ of migration) to the Australian landmass occurred around 45000 years ago, following which this population remained isolated until colonization by Europeans in the 18th Century. This study upends this conclusion.
How Does Such Genetic Analysis Work?
Before the era of airplanes and global migration, populations across the world were relatively isolated, mainly because of geographical barriers, and often because of cultural and social barriers. Thus, members of each population would only breed with other members of the same population. Over time, this lack of interbreeding, or genetic mixing between different populations, led to distinct patterns that could be seen in each population. It is by looking at similarities and differences in these that we can compare genetic data.
A Study of Global Populations
Researchers at the Max Planck Institute for Evolutionary Anthropology collected ‘genotype data’—genetic data only at commonly varying locations in the genome—from different populations across the world (see figure above), and looked for patterns of similarities across these populations in terms of their genetic data. Using this genetic data and known rates of genetic change, they found a genetic link between populations from Australia, New Guinea and Mamanwa (an ancient group from the Philippines). This is consistent with the ‘southern route’ theory. What was novel was a significant similarity between Indian populations and Australian populations. This indicates a pattern of gene flow from India to Australia approximately 4230 years ago, a period called the Holocene.
Genetic Link Matches Archaeological Record—Coincidence?
This is fascinating because of an archaeological factoid of this period. This represents the period when changes in tool technology, food processing and a dog native to Australia called the dingo emerged on the Australian subcontinent. Could this emergence be related to the migration occurring in the same period?
It is plausible that this wave of migration was not direct, i.e., it could have been through the region of S.E. Asia, which shares long cultural links with Australia. However, the patterns of similarity seen between the Indian and Australian populations are not seen in the South-East Asian populations which were also included in this study. This means that there was a direct migration between India and Australia.
The study of our past is a fascinating one. Genetic data is an invaluable tool in this pursuit, and provides a tangible way for mankind to trace its evolutionary past.
You can read about this research here.