Paleoamerican Odyssey Conference: Ancient Mal’ta DNA, Ice-Free Corridor, Back Migrations to the Old World, Craniofacial Diversity in the New World and Pre-Clovis
My complete paper delivered yesterday at the Paleoamerican Odyssey Conference in Santa Fe is now available here. I will keep updating this post as more information comes in. I’m keeping the news of Eske Willerslev’s ancient DNA analysis of Mal’ta and Afontova Gora under wraps until further notice. One of the highlights of Thursday night was a memorable dinner I had with Theodore Schurr, the co-presenter at the evening session, in which we hotly debated the out-of-America vs. out-of-Africa precepts across population genetics and linguistics. It’s always good to talk to Ted!
A couple of wins for out-of-America: Schurr acknowledged that it’s indeed puzzling that the so-called oldest human lineages such as mtDNA L and Y-DNA A and B are not found outside of Africa. They haven’t popped up in either ancient remains (all most ancient mtDNA samples belong to the most downstream macrohaplogroup, according to the current phylogenies) or at small frequencies in marginal populations of the Sahul or East Asia. If populations outside of Africa migrated from Africa, how come they do not carry with them any of the African genetic signatures? He also believes that there’s enough genetic evidence right now to talk about a back migration from the New World at the end of the Ice Age.
As always, hanging out with Alvah (Pardner) Hicks and his son Sam has warmed my heart. On the left, Alvah and I are standing in front of his poster presentation “Interpreting Archaeological Signatures Before Clovis.”
I was also delighted to meet Alexander Kim , of the David Reich Lab, who gave me a heads-up regarding the upcoming paper by their team as well as a news piece in Science by Michael Balter presenting the analysis of a number of ancient DNA samples from Eurasia in the context of possibly bi-directional gene flow between the Old and the New World.
My notes on a few notable presentations and posters can be found below.
Swisher, Mark E., Dennis L. Jenkins, Lionel E. Jackson, Fred M. Phillips
This poster presentation by a team of Canadian geologists argues that the ice-free corridor in northern North America was impassable for just 5,000 years between 20,000 and 15,000 YBP. Prior to 30,000 and after 14,500 YBP there was no ice-sheet coalescence between the Laurentide and Cordilleran ice-sheets enabling therefore human and animal movements back and forth between the New and the Old Worlds.
The Increasing Complexity of the Colonization Process: A View from the North American West
Beck, Charlotte, and George T. Jones
Contrary to the dominant expectation, dates and diversity all suggest the origin of Clovis in the southern part of the contemporary U.S. with subsequent northward population movements to the Northeast and the Northwest of the continent. In the northwest, Clovis-bearers encountered other pre-existing traditions such as Western Stem Point tradition and the Paisley Cave population.
Early Human Occupation of Lagoa Santa, Central Brazil: Implications for the Dispersion and Adaptation of Early Human Groups in South America
Hubbe, Mark, Walter Neves, Danilo Bernardo, Andre Strauss, Astolfo Araujo, Renato Kipnis.
Paleoamerican skulls such as Lagoa Santa cluster with, first, Australo-Melanesian and, then, African skulls. The whole group is contrasted with the modern American Indian, East Asian and European cluster (see on the left). Consequently, craniofacial variation in the Americas is as extensive as in the world as a whole. This said, the two clusters do overlap in a small portion of the sample (see below). The specialization into Caucasoid, Mongoloid andmodern Amerindian cranial types, therefore, took place after the initial colonization of the Americas. If one assumes an out-of-Africa model of human expansions, then the ancestral craniofacial type remained virtually unchanged during the whole process of human migrations beginning with an out-of-Africa exodus and ending with the colonization of South America. Phenomenal craniofacial diversity in South America parallels extensive linguistic differentiation in the continent and has parallels in population genetic studies as well.
I thank Mark Hubbe for generously sharing the PPT deck of his talk with me. His paper brings up the same cross-disciplinary data points that I have been bringing up on this blog and in my book The Genius of Kinship regarding the great biological and cultural diversity found in the Americas. The combination of linguistic, genetic and craniofacial diversity is a strong
argument against any theories of late peopling of the New World. Hubbe et al.’s argument that the ancestral craniofacial type remained unchanged both at the source and at the most terminal points of the purported journey out of Africa fits well with the similar observation by a) ethnomusicologists such as Victor Grauer that early musical forms found in Pygmies and Bushmen are also found in Papua New Guinea and Amazonia (see here and here); and b) by folklorists such as Yuri Berezkin who finds the same mythological motifs in Sub-Saharan Africa, the Sahul and South America. The Serial-Bottleneck hypothesis advanced by geneticists in the 1990s cannot explain this pattern.
Hubbe and I discussed the relative position of African “anatomically modern human” remains from the 200,000-100,000 YBP vis-a-vis Late Pleistocene hominins. Hubbe is positive that all Late Pleistocene hominins regardless of the continent form a single, closely tied cluster (his team, however, does not have in their dataset the Hofmeyr skull – the 35,000-year-old South African skull that clustered not with modern Africans but with Upper Paleolithic Eurasians). It contrasted, on the one hand, with such later regional variants as modern Amerindians, Mongoloids and Caucasians, and, on the other hand, with Mid-Pleistocene “anatomically modern humans” in Africa. The latter are far removed from Late Pleistocene humans without any transitional specimens in between. I found this assessment interesting because it leaves without support the commonly held assumption that “anatomically modern humans” are ancestral to living humans.
I communicated to Hubbe Peter Brown’s paper in which he suggested (p. 120) that considering that, chronologically speaking, the earliest skulls with generalized “Mongoloid” morphology appear in the New World, it’s possible that the Mongoloid phenotype evolved in Northern North America and spread from there to Asia at the end of the Ice Age (Out-of-America III). Hubbe was not aware of the Brown paper or of the chronology of “Mongoloid”-like skulls in the New World vs. East Asia.
Late Pleistocene Economic and Cultural Diversity in North Peru
Dillehay, Tom D.
Tom Dillehay’s talk was remarkable and amusing not because of its stated topic and main content but because of the remarks he made toward the end on the Toca da Tira Peia site in Brazil and its reception by such Clovis-I advocates as Stuart Fiedel. The lithic assemblages at the Toca da Tira Peia rockshelter were dated at 22,000 YBP. Fiedel suggested that they were made not by humans but by capuchin monkeys. In response, Dillehay defended the anthropogenic origin of the oldest layer at Toca de Tira Peia comparing it to the earliest tools from Monte Verde dated at 33,000 YBP. He mocked Fiedel for believing in tool-manufacturing monkeys and announced the new co-director of the Monte Verde project (see on the left).
This came on the heels of a more serious concern by Dillehay regarding the debilitating aspects of the Clovis-I vs. pre-Clovis debate, which, according to observers, has taken such brutal, shameful and counter-productive ad hominem attacks as to become detrimental to science. I have to admit humans sometimes behave like chimps toward each other, not like capuchins (see here, courtesy of reader Kelly).