The coverage in The Economist of a recent study of the genetics of Australian Aborigine populations is pretty thorough in introducing the possibility of some migration from South Asia to Australia in the era of the Indus Valley civilization, just over four thousand years ago. (Three cultural innovations mentioned in the article as possibly having South Asian antecedents include better tool technologies, new techniques for processing nuts for food, and maybe even the dingo.)
[A] study by Irina Pugach of the Max Planck Institute for Evolutionary Anthropology, in Leipzig, and her colleagues, which has just been published in the Proceedings of the National Academy of Sciences, [suggests that a]bout 4,000 years before Captain Phillip and his merry men arrived to turn the aboriginals’ world upside down [in 1788], it seems that a group of Indian adventurers chose to call the place home. Unlike their European successors, these earlier settlers were assimilated by the locals. And they brought with them both technological improvements and one of Australia’s most iconic animals.
Dr Pugach came to this conclusion by studying what are known as single-nucleotide polymorphisms, or SNPs. These are places where single pairs of the genetic “letters” that make up DNA often vary between individuals. (The letters themselves are chemical bases of four varieties, which pair up in specific ways, and which encode the instructions for making proteins, and thus living creatures.) SNPs act as markers for blocks of DNA that get swapped around during the process of sexual reproduction. Examining their pattern can therefore reveal a person’s ancestry—both where those ancestors came from, and when they lived.
[. . .]
There is a pattern of SNPs in aboriginal Australians that is not found in people from New Guinea or the Philippines. But it is found in some Indians—particularly in Dravidian speakers from the southern part of the subcontinent. That discovery both meshes with the Y-chromosome data and enriches it, because the pattern of the SNP data meant that she and her colleagues could calculate when the Indian genes (and thus the Indians who carried them) arrived in Australia.
The answer is 141 generations ago. Allowing 30 years a generation, that yields a date of 2217BC. Obviously, this is not a precise date. But it is probably good to within a century or two. And that is interesting for two reasons. One is that the 23rd century BC is slap-bang in the middle of the period when Indian civilisation was emerging. The other is that it coincides with a shift in both the culture of Australia and the composition of the continent’s wildlife.
The bronze-age Indus valley civilisation, which reached its peak of development between 2600BC and 1900BC, is less well-known to outsiders than its contemporaries in China and the Middle East, partly because no one has managed to translate its written records. But it was no less successful, and it led—just as those two other areas did—to an urban culture that resonates today.
One technology it managed to develop was seaworthy ships, rather than mere boats, and Indus valley states used them to trade with their Middle Eastern neighbours. Such ships could have provided the means to get to Australia, either deliberately or by accident, for by then the sea had risen close to its modern level.
Archaeological evidence suggests that the Indus valley civilisation did not extend into the area where the telltale SNP patterns came from, so any connection is speculative. But many anthropologists believe Dravidians were once more widespread than they are today. (There is, for example, a group of Dravidians living south of Quetta, in Pakistan, on the edge of the territory occupied by the Indus valley civilisation.) In any case, Dr Pugach and her team could find no sign of the relevant SNP pattern in South-East Asia. That suggests the people who brought it may have travelled directly across the Indian Ocean, rather than coasting through what is now Indonesia. If so, they probably came by ship, rather than boat.