There has been a recurring view in Australia that the Aborigines were a changeless people living in a changeless land. We now know that that view was incorrect on both counts. Aboriginal life did change over the millennia of Aboriginal occupation of the continent, while the land itself changed many times as climate changed and as the Aborigines themselves modified the land.
In all the discussion, the first settling of Australia has always been a question of interest to Australian prehistorians and anthropologists. When did the Aborigines first arrive in Australia, where did they come from and by what route? A second question of interest has been the issue of later settlement: did the original settlers and their descendants continue in unchallenged occupation of the land or were there new arrivals that challenged or at least mixed with the local population?
Anthropological, archaeological and ethnographic evidence all indicated some changes in the physical appearance of the Aboriginal population across time and space. Did those changes reflect new arrivals or were they within the range of normal physical adaptation to different environment over the millennia?
These questions are of both academic and political interest, for they play into the complicated debates surrounding Aboriginal history and associated discussion of rights of and treatment of Australia’s Aboriginal peoples.
New dating techniques have progressively pushed back the date of first arrival. It now appears that the Aborigines probably arrived in this country between 50,000 and 60,000 years ago during the Pleistocene period. Older sites may still be found, although the very earliest sites may lie below the sea; sea levels were then around 100 meters lower than the present levels.
In terms of route, two possible routes were postulated, southern and northern. The southern route went via what is now Indonesia where water distances were the shortest. The northern route went via what is now the Philippines through New Guinea. Water distances were much longer, but the prevailing winds may have assisted southern movement.
In 2002, a group of researchers published a paper in Current Biology. This concluded that there was tight clustering between elements of the Y chromosome among the Aborigines studied from Northern Australia and people living in Southern India and Sri Lanka. This was evidence of an Indian connection and a southern route. However, there was a further feature.
Using the dating techniques developed for estimating when gene streams diverged, they concluded that the results strongly suggested that there had been an influx of Indian genes during the much later Holocene period. They also noted that the timing coincided with a period of significant change among Australia’s Aboriginal peoples.
Around 5,000 years ago, the archaeological evidence suggests the beginning of a process of significant change in Aboriginal life, a process described by Harry Lourandos as intensification. I will deal with the intensification debate in another post. For the present, populations increased and there were significant changes in Aboriginal technology.
In 2009, a group of Indian researchers published a paper in BMC Evolutionary Biology that provided a different perspective on the question of connections between the Australian Aborigines and the Indian sub-continent. Using mtDNA sequencing, they concluded that there were genetic links between certain Indian tribal groups and the Australian Aborigines, but that the divergence had occurred between 50 and 60,000 years ago. To their mind, this provided conclusive evidence that the original Australian Aborigines and those living in Papua and New Guinea had followed the southern route via South Asia in first settling Australia.
This year, study led by researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany presented new results, again based on DNA evidence. found evidence of substantial gene flow between Indian populations and Australia about 4,000 years ago. In addition, the researchers found a common origin for Australian, New Guinean and the southern Philippine negrito Mamanwa populations. The researchers concluded that these populations followed an early southern migration route out of Africa, while other populations settled in the region only at a later date.
So what do we make of all this? On the surface, the evidence suggests that there were at least two migration flows, one via southern India at the time of first settlement and then a second one many years later. The Max Planck study also establishes an apparent common linkage between groups in Australia, New Guinea and the Southern Philippines. However, if as the Max Plank researchers conclude, they all followed the southern route, that suggests migration north from New Guinea into the Philippines against the winds.
We need further DNA analysis to resolve all this!
 Alan J Redd, June Roberts-Thomson, Tatiana Karafel, Michael Bamshad, Lynn B Jorde, J M Naidu, Bruce Walsh and Michael F Hammer, Gene Flow from the Indian Subcontinent to Australia: Evidence from the Y Chromosome, Current Biology, Vol 12, pp673-677, April 16, 202. Accessed on-line http://nitro.biosci.arizona.edu/zdownload/papers/CurrentBiology.pdf 18 January 2013
 Satish Kumar, Rajasekhara Reddy Ravuri, Padmaja Koneru1, BP Urade, BN Sarkar, A Chandrasekar and VR Rao, Reconstructing Indian-Australian phylogenetic link, BMC Evolutionary Biology, 9:173, accessed on-line 18 January 2013 http://www.biomedcentral.com/content/pdf/1471-2148-9-173.pdf
 Max Planck Institute for Evolutionary Anthropology, Gene flow from India to Australia about 4,000 years ago, accessed online 18 January 2013, http://www.mpg.de/6818105/Holocene-gene-flow_India-Australia