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Human
09-17-2012, 09:58 PM
Considering the excitement over the past two years regarding "evidence" that there was hybridization between our two species, I thought this was an appropriate article to share in its own, dedicated thread. The hypothesis that hybridization occurred has been accepted by many. Even 23andme now shows your % Neanderthal result. However, this hypothesis is being challenged. The hybridization hypothesis is based upon the assumption that our shared DNA (i.e., to be specific, shared polymorphisms - "markers" in DNA) is the result of hybridization. Now, we are seeing more evidence that this shared DNA may actually be simply due to our common ancestry with archaic species.

http://www.sciencedaily.com/releases/2012/08/120813155521.htm

From the Scientific Literature
http://www.pnas.org/content/109/35/13956.short

GailT
09-18-2012, 04:08 AM
Considering the excitement over the past two years regarding "evidence" that there was hybridization between our two species, I thought this was an appropriate article to share in its own, dedicated thread. The hypothesis that hybridization occurred has been accepted by many. Even 23andme now shows your % Neanderthal result. However, this hypothesis is being challenged. The hybridization hypothesis is based upon the assumption that our shared DNA (i.e., to be specific, shared polymorphisms - "markers" in DNA) is the result of hybridization. Now, we are seeing more evidence that this shared DNA may actually be simply due to our common ancestry with archaic species.


This paper has been described as "obsolete" before it was published, perhaps due to long publication delays at PNAS. John Hawks (http://johnhawks.net/weblog/reviews/neandertals/neandertal_dna/neandertal-ancestry-iced-2012.html) and Razib Khan have both commented on the paper. John seems very confident that his results show there was interbreeding between modern humans and Neadandertals, in addition to the possibility of archaic mixing within Africa.

Jean M
09-18-2012, 08:43 AM
John Hawks is not exactly neutral on this issue. He has been one of the strongest proponents of the idea. Frankly I remain unconvinced. So far the evidence seems much stronger of interbreeding with Denisovans, leaving traces only in a small proportion of modern humans (in Papua New Guinea, Australia etc).

Ian B
03-18-2013, 01:15 AM
John Hawks is not exactly neutral on this issue. He has been one of the strongest proponents of the idea. Frankly I remain unconvinced. So far the evidence seems much stronger of interbreeding with Denisovans, leaving traces only in a small proportion of modern humans (in Papua New Guinea, Australia etc).

The following from Wikipedia will not be news " The origin of Aboriginal peoples in Australia has been the subject of intense speculation since the nineteenth century. Until recently, no theory of migration had gained wide acceptance. Genetic studies had shown the Aboriginal peoples to be related much more closely to each other than to any peoples outside Australia, but scholars had disagreed whether their closest kin outside Australia were certain South Asian groups, or instead, certain African groups. The latter would imply a migration pattern in which their ancestors passed through South Asia to Australia without intermingling genetically with other populations along the way. [13] (http://www.anthrogenica.com/#cite_note-13) A 2009 genetic study in India found similarities among Indian archaic populations and Aboriginal people, indicating a Southern migration route, with expanding populations from Southeast Asia migrating to Indonesia and Australia.
In a genetic study in 2011, researchers found evidence, in DNA samples taken from strands of Aboriginal people's hair, that the ancestors of the Aboriginal population split off from the ancestors of the European and Asian populations between 62,000 and 75,000 years agoŚroughly 24,000 years before the European and Asian populations split off from each other. These Aboriginal ancestors migrated into South Asia and then into Australia, where they stayed, with the result that, outside of Africa, the Aboriginal peoples have occupied the same territory continuously longer than any other human populations. These findings suggest that modern Aboriginal peoples are the direct descendants of migrants who arrived around 50,000 years ago.[14] (http://www.anthrogenica.com/#cite_note-14) This finding is supported by earlier archaeological (http://www.anthrogenica.com/wiki/Archaeological) finds of human remains near Lake Mungo (http://www.anthrogenica.com/wiki/Lake_Mungo) that date to 45,000 years ago. In the same genetic study of 2011 it was found evidence that Aboriginal peoples carry to one degree or another some genes associated with the Denisovan (http://www.anthrogenica.com/wiki/Denisovan) peoples of Asia, the study suggests that there are an increase in allelee sharing between the Denisovans and the Aboriginal Australians genome compared to other Eurasians and Africans. Nevertheless the Papuans have more sharing alleles than Aboriginal peoples, these data suggests that modern and archaic humans interbred in Asia before the migration to Australia.[15] (http://www.anthrogenica.com/#cite_note-Callaway.-15)"


Another explanation could be that interbreeding between Papuans and Denisovans continued after the Australian Aborigines settled in Australia. The Papuans could be representative of a later migratory wave. Nevertheless, Australian Aboriginal people, prior to white settlement, were the last examples of Stone Age man.