May 19, 2012

African genetics international conference (video)

A bunch of talks from the African Genetics International Conference have been posted.

You can refer to this list of talks.

I haven't watched any of the videos yet; feel free to comment on any interesting nuggets of information in them.

A few that I plan to watch:

(UPDATE: A very interesting bit at around 42')

Beyond Eden: The Significance of Archaic Human Genetic Sequences in African Populations

Michael Hammer, University of Arizona

The following video has been pixelized, presumably because it includes pictures of unpublished data (?)

Paleoanthropological Origins of Human Genetic Diversity: The Significance of humanity’s African Roots

Chris Stringer, Natural History Museum, London

Technological Innovations Impacting Genomic Science

George Church, Harvard & MIT


eurologist said...

Thanks for posting the videos - they are definitely educational.

I like Stringer's embracing of Heidelbergensis - my thought for many, many years (perhaps it's a difference between the European view vs. what used to be a more widespread US thought on the topic).

Unfortunately, both didn't go any further on the green Sahara, and didn't mention the adjacent green Arabia and associated stone tool sets, nor the importance of a possible back-migration into Africa. Stringer was a bit off there with some of the dates - also confusing mtDNA last-common-ancestor dates with the average autosomal one.

Did I understand Hammer correctly that up to 15% of the African genome could be archaic?

Jim H. said...

Stringer covers that material but with only monochrome illustrations in his excellent 2011 book (Amazon UK)
Different title in US --

George said...

Michael Hammer talked about the New High Priests in his field.


I am a just a lay person (worshiper) and was wondering if Dienekes, Razib Khan and others could comment on this and provide their own lineup of 5 or so "Priestly" persons.

I actually have some skin in this game as my new son inlaw is about to graduate with a Bachelors in Anthropology .... and then I guess he needs a Masters and PHd until he can start bringing home some bucks.

Also, what's others take on Hammer's comments on the Jolly Babboon Analogy?

Onur Dincer said...
This comment has been removed by the author.
Onur Dincer said...

Interesting findings about relatively high level of archaic admixture in Negroids, in line with the degree of their genetic distance to non-Negroids. Pygmies seem to show expecially high levels of archaic admixture. I think this is the reason behind their genetic divergence from the rest of the extant modern humans. I am sure the San would show similarly high levels of archaic admixture if they were examined.

As Stringer pointed out, it would be interesting to test the hypothesis that the differences between the phenotypes of the extant human races are mainly due to different types and levels of archaic admixture. Here is my guesstimate of the ordering of the extant human races based on the level of archaic admixture from the lowest to the highest: Caucasoids - Mongoloids (including Amerindians) - Australoids - Negroids (hunter-gatherer Negroids having the highest level of archaic admixture).

Unknown said...

"Interesting findings about relatively high level of archaic admixture in Negroids"

Hammer only mentions the Biaka Pygmies in this context not other Africans. The estimate, which is still unconfirmed, for this group, was approximately 7.5-10%(described in the video as three to four times the archaic in Europeans). Hall and Hammer's estimates have been off in the past. They estimated at least 5% Neanderthal in Europeans when the average is in fact about 2.5%.

Dienekes said...

It is clear -I've written about this as well- that the evidence for archaic admixture depends on the recency of the admixture event, because otherwise recombination removes the evidence for it (the archaic "chunks" of DNA become so small that the statistical case for them being archaic weakens).

Another great point made by Hammer is that the 2.5% is not actual admixture, but an _excess_ of admixture in Eurasians relative to Africans. He also makes another of my points, namely that the D-statistic based admixture estimates can be explained by either Neandertal admixture or African structure, and he's unsure which of the two processes explains most of it.

Onur Dincer said...

Hammer only mentions the Biaka Pygmies in this context not other Africans.

Incorrect. In the 42nd minute of the video Mike Hammer presents the results of a soon-to-be-published study by Jeffrey (Jeff) Wall according to which archaic admixture in Negroids in general (not just Pygmies) is a few times higher than in non-Negroids. Biaka Pygmies have the highest archaic admixture level according to Wall's study. Unfortunately the San are not included in that study.

Onur Dincer said...

He mentions Africans without specifying which ones, and then describes the admixture in the Biaka as a few times higher. It is not clear whether he means Africans in general, certain African groups, or one.
I do not believe he mentions "Negroids". As far as I know Subsaharans do not form a single cluster genetically. The divergences between Khoisans plus Hadza/Sandawe, Pygmies and most non foraging groups appear deep. West Africans and the "purer" Nilo-Saharan speakers of South Sudan(according tovTischkoff) seem to have diverged near the holocene.

He compares the archaic admixture levels in Negroids and non-Negroids according to the results of Wall's study and explicitly states that Negroids (he uses the word "Africans" to designate them) are much more archaic admixed than non-Negroids (he uses the word "non-Africans" to designate them) according to Wall's study and the chart he shows confirms that. He explicitly mentions Biaka Pygmies because they are the most archaic admixed of the studied Negroid populations, but from the chart it is clear that in addition to Pygmies two other Negroid populations were examined in that study (I know those two Negroid populations from earlier genetic studies). The three Negroid populations are from different parts of Sub-Saharan Africa and have very different traditional subsistence types and population histories, so they can represent Negroids in general when making a Negroid/non-Negroid comparison.