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Friday, November 23, 2018

Levallois tools: did this technology originate in Asia?


Earlier this year, a paper (Kumar Akhilesh et al., Early Middle Palaeolithic culture in India around 385–172 ka reframes Out of Africa models, Nature volume 554, pages 97-101, 01 February 2018) reported finding Levallois stone tools in a site called Attirampakam, in India. These tools were about 385,000 years old, which put the date of this stone knapping technology further back in time than had been previously expected.


These Indian tools are even older than the Levallois tools found in Africa, and they predate the currently accepted date of Homo sapiens expansion out of Africa.


Modern Brains


The Levallois tools represent a shift in stone knapping know-how. Until then the Acheulian (developed by Homo erectus) technique had been in use for over 1.4 million years.


It was named after the site where they were first discovered in the 1800s: Levallois-Perret, a suburb of Paris, in France.


It is distinctive of a more brainier hominid, who developed a new technique for knapping stones to obtain sharp flint tools.


But who made them? until recently it had been suggested that they were the result of archaic Homo sapiens migrating out of Africa.


But with the Indian tools dated around 385 kya and some found in Armenia (D.S. Adler et al., Early Levallois technology and the Lower to Middle Paleolithic transition in the Southern Caucasus, Science 26 Sep 2014: Vol. 345, Issue 6204, pp. 1609-1613 DOI: 10.1126/science.1256484) aged 325 kya, this explanation seems unfounded: there were no H. sapiens at that time.


Adler writes: "Our data from Nor Geghi, Armenia... are consistent with the hypothesis that this transition occurred independently within geographically dispersed, technologically precocious hominin populations with a shared technological ancestry."


Suggesting a pre-Homo sapiens origin.


The oldest remains of Homo sapiens and Levallois tools are from a site in Morocco and they are much more recent than the Armenian and Indian tools: 315,000 years old. (Read more).


We know that the Neanderthal made them in Europe, could they be the authors of these Eurasian tools?


A paper published four days ago: Yue Hu et al.Late Middle Pleistocene Levallois stone-tool technology in southwest China, https://doi.org/10.1038/s41586-018-0710-1 DO 10.1038/s41586-018-0710-1 ID Nature 19. Nov. 2018), reports finding Levallois tools in China:


"Here we present evidence of Levallois technology from the lithic assemblage of the Guanyindong Cave site in southwest China, dated to approximately 170,000-80,000 years ago. To our knowledge, this is the earliest evidence of Levallois technology in east Asia. Our findings thus challenge the existing model of the origin and spread of Levallois technologies in east Asia and its links toa Late Pleistocene dispersal of modern humans."


So once again who made them? This date is prior to any known H. sapiens presence in China. Were they Neanderthals? or perhaps Denisovans, who lived in Southern and Central Asia at that time?


Here we have a technological break-through that seems to have originated Out of Africa and not In Africa, our purported craddle of mankind. Did modern humans evolve outside of Africa?


Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2018 by Austin Whittall © 

Saturday, November 3, 2018

HPV Neanderthals, Africans and the early peopling of America


Almost two years ago I posted about HPV16 and Humans, Neanderthals, Denisovans and the Out Of Africa theory, and asked an open question about some oddities in the global distribution of HPV lineages: "Why is "D" highest in the Americas if it is supposed to have originated in Africa (see further up)... slave trade by Europeans? We'd need to see Karitiana or Coya, Pima haplogroups...".

I also made a comment and aked a second question because it turned out that the American HPV was more diverse than the Old World variants... which is unusual, considering that Amerindians are always considered as the least diverse humans (the famous Beringian bottleneck!). My comment and question was:


"And the diversity again: "East Asian and Central American HPV16 isolates showed higher average number of pairwise differences compared with sub-Saharan African isolates, even after accounting for intralineage diversity.", what? something in America more diverse than in Sub-Saharan Africa... why?"


A paper published two days ago (Nov. 1, 2018) has revisited HPV and provided answers and more data on these issues. (Chen Z, DeSalle R, Schiffman M, Herrero R, Wood CE, Ruiz JC, et al. (2018) Niche adaptation and viral transmission of human papillomaviruses from archaic hominins to modern humans. PLoS Pathog 14(11): e1007352. https://doi.org/10.1371/journal.ppat.1007352).


The paper suggests that HPV originated in Africa and that some 618,000 years ago (roughly at the time that Neanderthals and our Homo sapiens ancestors were splitting apart) an ancient HPV variant "A" split from the variant that would become lineages "B", "C" and "D".

Neanderthals left Africa with HPV A, which over the next few hundreds of thousands of years evolved into sublineages A1, A2, A3 and A4, all found in Eurasia, and in America, but very very rare in Africa.

Modern H. sapiens then left Africa 120-60 Kya and had sex with Neanderthals, picking up the HPV virus in its A variant sublineages. The African "B" and "C" variants are preponderant in that continent, with very small proprotion in Eurasia (5.6% among Caucasians and 1.8% among Asians) and America (2.3%). And the American "D" variant, according to this paper, originated in Africa, passed through Eurasia where it is found in extremely small amounts among Caucasians (11%) and Asians (6.3%). It entered America where it represents 48.3% of the HPV lineages.


Surprisingly the A4 variant that is 29.9% prevalent in Asia and 0.4% among Eurasian Caucasians, does not appear among Americans.


The authors sampled 212 complete genomes and built a phylogenetic tree of the different HPV16 variants based on this data. This tree shows two separate clades which coincides with previous findings, which had identified an Eurasian and an African lineage. They identified four lineages and named them A, B, C and D. These in turn were subdivided into four sublineages (A1 to 4, B 1 to 4, etc.). The breakdown of lineages is the following, where the percentages indicate their proportion in each population:

  • A1 to A3: Eurasia (83% among Caucasians, 62% among Asians)and America (49.5%), only 2.4% prevalence in Africa.
  • A4: As mentioned above prevalent in Asia (29.9%) and very little of it found elsewhere (0.4% among Caucasians) and nill in America and Africa.
  • B: African (54.2%), 4% in European Caucasians, 0.2% in Asians and 0.5% among South and Central Americans.
  • C: African (36.1%), 1.6% among European Caucasians and 1.6% among Asians. 1.7% in South and Central Americans
  • D: America (48.3%), 7.2% in Africa, 11% in Europe, 6.3% in Asia.

Distribution of HPV16 lineages. From Schiffman M, Herrero R, Wood CE, Ruiz JC, et al.

The paper reports that there was more diversity in the African variants with an intragroup mean difference of 0.77% ± 0.04% compared to the Eurasian variants (0.32% ± 0.02%).

However the maximum divergence between sublineages was between the Eurasian A1 and the American D3 (2.23%) as can be seen in the Heatmap of pairwise diversity, which shows all of the 212 sequenced HPV16 genomes the maximum 2.23 difference is shown in red, and the minimum diferences are shown in blue. Amerindian D is therefore the most diverse.


So, summing up BCD and A split 618 thousand years ago, "indicative of an ancient divergence of HPV16 variants prior to the emergence of modern human ancestors".

The authors state: "The estimated divergence times between HPV16 A and BCD variants largely predated that of the out-of-Africa migration of modern human populations, consistent with a previously reported archaic hominin-host-switch scenario [19, 20]. One interpretation of the data implies that the present-day Eurasian HPV16 A variants were probably the products of multiple interactions between Neanderthals/Denisovans and modern Homo sapiens established during sexual contact after a long period of separation (e.g., 400–600 kya)"


The odd situation of the "D" variant (so diverse yet almost unique to America) is explained as follows (bold face is mine):


"Following a relatively recent out-of-Africa migration, the modern humans acquired the A variant from sex with archaic hominins and possibly carried D variants into Eurasia under conditions of a small population size. The ancestors of East Asian people crossed the Bering Strait and were early populators of the Americas (based on historical records and genetic relatedness). Surprisingly, the D lineage is phylogenetically rooted in the African clade, but we did not find a major reservoir of the D lineage in the present-day African populations. This interesting observation suggests either an advantage of niche ` colonization and expansion of HPV16 D variants in Native Americans or a bottleneck of HPV16 variants present in people populating the Americans. Alternatively, the lack of A4 and the high proportion of D lineages in the Americans could be the result of an early colonization of the Americas by an unknown group from Africa. More data is needed to sort out the evolutionary history of the HPV16 D lineage and might provide clues to new features of the populating of the Americas."


The idea of an "unknown group from Africa" colonizing America at an early date is very interesting. And the authors realize that this D lineage is special because in their closing comments they add: "Lastly, we provide new interpretations and questions on the HPV16 D lineage that is part of the African clade, but is highly prevalent in South/Central America.".



Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2018 by Austin Whittall ©