Post by Bozur on Dec 16, 2011 13:54:57 GMT -5
August 06, 2010
A rare genomic look at Aboriginal Australians
How strange that modern genetics is supposed to have invalidated the concept of race, yet, at every turn, it confirms most of the basic racial taxonomic observations of people working only with their eyes and, much later, their calipers.
On the left is the frappe analysis from the supplementary material, the Oceanian populations are seen on the far right.
The Australasid cluster emerges as an entity at K=5, showing Caucasoid admixture (AUR), Mongoloid admixture (MEL), and no apparent admixture (PAP).
At K=8 it is evident that the Caucasoid admixture in Aboriginal Australians is specifically European in origin, certainly the result of colonization in very recent times.
What can account for the Mongoloid admixture in Melanesians? It is probably the recent spread of Austronesian languages, arguably the most epic maritime language spread before Columbus, which affected a good deal of the southern hemisphere from Madagascar through Indonesia, Micronesia, Melanesia, and all the way to Polynesia on the far end.
As for the unadmixed Papuans, the indigenous inhabitants of New Guinea, their results are not surprising: there is a lack of admixture of East Asian Y chromosomes on the island, even in its most affected NW corner (Bird's head) where this admixture runs only to about 2.5%.
The American Journal of Human Genetics, doi:10.1016/j.ajhg.2010.07.008
Whole-Genome Genetic Diversity in a Sample of Australians with Deep Aboriginal Ancestry
Brian P. McEvoy et al.
Australia was probably settled soon after modern humans left Africa, but details of this ancient migration are not well understood. Debate centers on whether the Pleistocene Sahul continent (composed of New Guinea, Australia, and Tasmania) was first settled by a single wave followed by regional divergence into Aboriginal Australian and New Guinean populations (common origin) or whether different parts of the continent were initially populated independently. Australia has been the subject of relatively few DNA studies even though understanding regional variation in genomic structure and diversity will be important if disease-association mapping methods are to be successfully evaluated and applied across populations. We report on a genome-wide investigation of Australian Aboriginal SNP diversity in a sample of participants from the Riverine region. The phylogenetic relationship of these Aboriginal Australians to a range of other global populations demonstrates a deep common origin with Papuan New Guineans and Melanesians, with little evidence of substantial later migration until the very recent arrival of European colonists. The study provides valuable and robust insights into an early and important phase of human colonization of the globe. A broader survey of Australia, including diverse geographic sample populations, will be required to fully appreciate the continent's unique population history and consequent genetic heritage, as well as the importance of both to the understanding of health issues.
dienekes.blogspot.com/2010/08/rare-genomic-look-at-aboriginal.html