Aboriginals - how did they get there, and are they related to amazonians?

[Adie]

Hi Folks.. first post, pls excuse me if this is already discussed to death..

But posting here because I find the idea that Aboriginals took a boat from Asia to Australia, some 50k years ago and those indigenous people in Aussie now are the results of that boat, a little bit difficult to swallow.

The boats men created 50000 years ago were probably not that great, given that we are talking about south asian hunter gatherers from the stone age. So how many of them were on a boat, I guess there must be male and females, otherwise these settlers wouldnt of lasted very long. So we have to believe that stone age man (and family) were cruising around SE Asia on boats, exploring, looking for a new land.

But its interesting to learn that apparently the Aboriginals did not come up with a an actual dug-out canoe until the 17th century, before this they were using canoes of animal skins (probably not great for transporting families around in). So did they forget how to make boats? Possible I guess..

However, what I find really puzzling are the recent revelations that some Amazonian tribes and Aboriginals share ancestry, however its not shared with northern amaerican indians.. So how did those amazon indians get there from Aussie?

Also interesting to learn taht the oldest remains of aboriginals have been found in SOUTH australia, dating back some 50k years.. Big country.. Youd expect to find bones in the North, given that they were supposed to have landed up there first..

So whats the deal?

 

[ThirdTerm]

WADE, NICHOLAS. "From DNA Analysis, Clues to a Single Australian Migration." The New York Times 8 May 2007: F4. Print.

Around 50,000 years ago, Australia and Papua New Guinea were geographically attached to each other and it would not have been too difficult to migrate to Australia from Southeast Asia without sophisticated canoes. Denisovan admixture, which is typical in Southeast Asia, was detected in some Latin American populations and some ancient Pacific islanders from Melanesia managed to reach Latin America through island hopping by 1,600 B.C. Australian Aborigines and the people in Papua New Guinea share several ancient genetic lineages, indicating that both are descended from an early Asian expansion wave some 62,000 to 75,000 years B.P. (Rasmussen et al. 2011).

The Australian individual’s mitochondrial genome (mtDNA) was sequenced to an average depth of 338×. It belongs to a new subclade of haplogroup O (hg O) that we term hg O1a (4). Haplogroup O is one of the four major lineage groups specific to Australia and has been reported from various parts of the Northern Territory (15 to 16%) (15–17). From high-confidence Y-chromosome SNPs, we assigned his Y chromosome to the K-M526* macro-haplogroup (4). Although the O and P branches of haplogroup K-M526 account for the majority of East and West Eurasian Y chromosomes, the unresolved K-M526* lineages are more common (>5%) only among contemporary populations of Australasia (15, 18). Both uniparental markers fall within the known pattern found among contemporary Aboriginal Australians (15), providing further evidence that the genomic sequence obtained is not contaminated.

In the case of the Denisovans, we used a D test (22, 23) to search for evidence of admixture within the Aboriginal Australian genome. This test compares the proportion of shared derived alleles between an outgroup sequence (Denisovan) and two ingroup sequences. This test showed a relative increase in allele sharing between the Denisovan and the Aboriginal Australian genomes, compared to other Eurasians and Africans including Andaman Islanders (4), but slightly less allele sharing than observed for Papuans. However, we found that the D test is highly sensitive to errors in the ingroup sequences (4), and shared errors are of particular concern when the comparisons involve both an ingroup and outgroup ancient DNA sequence. Although we cannot exclude these results being influenced by such errors, the latter result is consistent with the hypothesis of increased admixture between Denisovans or related groups and the ancestors of the modern inhabitants of Melanesia (23). This admixture may have occurred in Melanesia or, alternatively, in Eurasia during the early migration wave.

 

[Adie]

Thanks, that helps. I think the gap in my knowledge was that the water levels were a lot lower and hence the distances shorter between land masses. Can I ask where you got that image from which shows the land masses from 50k yrs ago?

 

[bicicleur 2]

there were 2 countries as you can see on the map in the prior post : the Sundaland peninsula and the Sahul Island.
Sundaland was densely forested and nobody lived in the forests, they all stayed along the shores whcih are now submerged, so they left very few traces.
At least 50 ka people arrived on Sahul. 49 ka people lived on the New Guinean highlands near the tree border which was then about 2000 meter altitude.
44 ka people started to explore the islands east of New Guinea, the were very skilled seafarers and they discovered the islands of what is now Melanesia, but not further east.
First people in Sundaland and Sahul were probably some tribes now extinct and D, C1b and C2.
Much later also K2b1, K2c, K2d and P2 arrived.
14 ka Sundaland started to drown because of rising sea levels and people started to hunt in the forests.

5,5 ka rice farmers moved in from China displacing many hunters that fled from Sundaland to Sahul.
Last major migration happened only 3,5 ka from Celebes to major parts of Australia. These people would have brought the dog, the dingo to Australia.

Polynesia and the other islands east of Melanesia were not discovered by these people, they were discovered by people related to the Chinese rice farmers. They are haplogroup O. They came from Taiwan via the Philipines through Melanesia. Another group sailed west as far as Madagascar.