A role-playing board game on Paleolithic hunter-gatherers

Millán Mozota, reader of this blog and author of a Neanderthal-specialized one in Spanish language, mentions today the existence of a new role-playing game on Paleolithic hunter-gatherers in the European landscape of some 35,000 years ago. 

The game is titled Würm, for the last Ice Age, which bears that name in Europe, and it deals with the adventures of hunter-gatherers of both species believed to have coexisted in that space-time: H. neanderthalensis ("bear-men" in the game) and H. sapiens ("long men"). 

As happens with this kind of games, all the basic material is a rulebook, available for download in PDF format HERE. A de luxe edition is also available HERE (€29.95). The problem for most readers of this blog will surely be that it only seems available in French by the moment. 

Still I must welcome the idea because it is something I have always found missing in the offer of games. And the usual dynamics of role-play games (party of adventurers and such, think The Lord of the Rings if you are unfamiliar) adjusts almost ideally to the kind of dynamics a small hunter-gatherer band would have faced in those times. 

Also, in addition to the thrill and enjoyment of any game, it adds educative value, as the game seems to be rather well documented. Hopefully the game will be successful enough to be translated to other languages. 

Neanderthal and Sapiens newborns were not that different

Also a brief note for Neanderthal-addicts (and in general people interested in human evolution): there is a new open access article at Current Biology on Neanderthal newborn head physiognomy (found at Dienekes). It seems that baby Neanderthals were somewhat but not too different from those of our species. This similitude may be caused by the physiological constraints of birthgiving, because as the adults develop the differences increase quite a bit.

Video: Lower and Middle Paleolithic knapping

The video illustrates and almost makes it look easy the three classical modes of knapping prior to Upper Paleolithic (Spanish/English text but notice that the word silex should translate as flint and is not translated):

Mode 1: Oldowayan or Chopper industries, usually related with H. erectus

Mode 2: Acheulean, usually related with H. ergaster and derivates

Mode 3: Mousterian and MSA, Levallois technique, usually related with H. neanderthalensis and early H. sapiens

Found at Pileta de Prehistoria, uploaded at YouTube by historiaunlu.

A note on West Eurasian haplogroups

Some aspects of the recent discussion in the previous post, got me thinking about West Eurasian founder effects, or major haplogroups and the possibility that they may reflect a number of coalescence areas or populations. 

So I got to consider the founder lineages of West Eurasians, let's see:

mtDNA:

• Major: R0 (incl. HV), U (incl. K), JT
• Minor: N1 (incl. I), X, W, M1
• Uralic-related: CZ, D (probably later arrivals via Siberia)
• African flows: L(xM,N) (not going to detail them here)

Y-DNA:

• Major: R1b, IJ, G and maybe R1a (or a subclade of it)
• Minor: T, L, Q
• Uralic-related: N
• African flows: E1b1b1

Something that is quite apparent is that the number of lineages in each category (specially if we ignore the Uralic and African groups, which clearly belong to different processes) are not too different between Y-DNA and mtDNA, what suggests that each pair represents a founder population, specially among the major haplogroups. Another thing is how to pair them and even if doing that makes any sense at all but it's quite possible that at the beginnings of the colonization of West Eurasia they were coupled to a great extent because of the well known phenomenon of fixation by drift in small populations. 

So I am guessing that there were like up to six or seven founder populations (maybe less as fixation does not need to be absolute, specially not in expansive contexts) some 50 millennia ago in West Asia. If we only consider the major clades, maybe these were just three.

Where did they exist? That I'll leave up to you. The details of the MP-UP transition in West Eurasia are not fully well understood and there seems to be blanks in the research. Some specific regions can be Palestine (clearly so), Central Asia, the Zagros mountains... an oasis area in the Persian Gulf (now submerged) has been proposed recently too... parts of Anatolia surely played a role, though here is where one of the most critical blanks exist...

Anyhow, most if not all these lineages are wildly scattered, so, while their West Asian origin is certain, the exact locations in this area are not at all clear. Maybe I am wrong and they were all part of a single founder population with only some, now blurred, structure. 

As I say, just a working note. Thinking loud so you feel free to provide feedback and opinions. Cheers.

Chimps and humans diverged some eight million years ago

I have said that several times. So I'm not going to miss the opportunity of saying it once more: the 5 million year figure for the Pan-Homo divergence is a total nonsense: it's more like 8-10 million years. Even the less exaggerated hunch (not sure on what is based) of 7 million years is too short.

New research, using mathematical-statistic analysis with not one but several cross-references, produces an older figure: some 8 million years.

Richard D. Wilkinson et al., Dating Primate Divergences through an Integrated Analysis of Palaeontological and Molecular Data. Systematic Biology, 2010. Pay per view.

Abstract

Estimation of divergence times is usually done using either the fossil record or sequence data from modern species. We provide an integrated analysis of palaeontological and molecular data to give estimates of primate divergence times that utilize both sources of information. The number of preserved primate species discovered in the fossil record, along with their geological age distribution, is combined with the number of extant primate species to provide initial estimates of the primate and anthropoid divergence times. This is done by using a stochastic forwards-modeling approach where speciation and fossil preservation and discovery are simulated forward in time. We use the posterior distribution from the fossil analysis as a prior distribution on node ages in a molecular analysis. Sequence data from two genomic regions (CFTR on human chromosome 7 and the CYP7A1 region on chromosome 8) from 15 primate species are used with the birth–death model implemented in mcmctree in PAML to infer the posterior distribution of the ages of 14 nodes in the primate tree. We find that these age estimates are older than previously reported dates for all but one of these nodes. To perform the inference, a new approximate Bayesian computation (ABC) algorithm is introduced, where the structure of the model can be exploited in an ABC-within-Gibbs algorithm to provide a more efficient analysis. 

Press article at Science Daily.

A central issue is that fossils are seldom preserved and discovered, so fossil evidence can well be five or 5.5 million years old and the divergence be in fact older.

But combining fossil and genetic data it is possible to refine the equation and get to much more accurate estimates. That's what the authors have done in what should be celebrated as a the convergence of genetics and archaeology (paleontology in this particular case), a convergence much needed indeed. 

Toumaï

One of the particular fossils which find new room into the potential Human ancestry is Sahelanthropus tchadensis, Toumaï, which fits well in the evolutionary line of Homo sp. but was earlier thought by many as too old for that.

Another aspect vindicated by this study is that primates lived in the late era of the dinosaurs, what really allows them to have reached South America without need of swimming across an ocean which did not actually exist yet. 

This was actually addressed by the same team in 2002 but its obvious implications in human evolution were ignored. So they have now decided to address the matter themselves, what is very much appreciated, because they must be damn right.

Related posts (also from my old blog Leherensuge):

• Very low mutation rate, mwahahaha! (I also thought to brag here but the merit is not mine and once is enough)
• Molecular clock speculation obscuring the real Jurassic origin of primates
• New paper on Chimpanzee and Bonobo genetics (it deals with research on the Pan genus that must push the Homo-Pan divergence to at least 8 million years ago, on hindsight a more important post than the title suggests).

Malaria and sickle cell anemia do not correlate well in Asia

There is an interesting new article that confirms by statistical means the long held theory that sickle cell disease exists in a dynamic equilibrium with the deadly disease of malaria, at least in general.

Federic B. Piel  et al., Global distribution of the sickle cell gene and geographical confirmation of the malaria hypothesis. Nature communications 2010. Open access.

What I find interesting is not so much the confirmation of a correlation in Africa and Europe but the lack of confirmation in Asia and Oceania, where malaria exists endemically too and, unlike the case of America, the discontinuity cannot be explained by loss of the sickle cell allele in the arctic latitudes (Beringia). In fact the peculiarities of the geographical distribution of sickle cell disease versus endemic malaria are very intriguing:

Fig. 1 (click to enlarge)

I understand that, in the case of Africa, the correlation is very strong, though not totally lineal. For instance the HbS (sickle cell) allele is lacking in wide areas of malaria endemism: The Horn, Southern Africa (including Bantu Mozambique but not Austronesian Madagascar), NW Africa...

So somehow these populations have managed to get rid of the sickle cell anemia in spite of being exposed to malaria in hyperendemic form. This alone is pretty interesting in itself, specially as it involves Bantu populations that are supposed to have expanded recently. 

In Europe we have two situations: Greece and Albania where sickle cell exists in moderate frequencies and the rest, where it is unheard of. While Greece is one of the malaria epidemic areas, there are others where the parasite has only been eradicated in the 20th century: Italy and Iberia specially. However no sickle cell exists there. This case is very suggestive, statistics apart, with the spread of Y-DNA E1b1b1a2 (V13), haplogroup that is most concentrated in the SW Balkans.

But most intriguing of all may be Asia. The presence of the allele in West Asia makes some good sense because of its prehistorical (and maybe also historical) interactions with Africa, so the HbS allele had all opportunities to arrive, really. 

But what about further East. We know of no particular "recent" genetic flow into South Asia that could explain the relatively high frequencies found in India, mostly in areas of lesser West Eurasian influence. The connections with Africa are even less likely (some small populations of recent African origin do exist but they cannot possibly have influenced the majority in such dramatic way in such short time).

It could be something arrived in the migration out of Africa of course, yet, on the other hand, further East there is no trace of the HbS allele. But malaria is found again in hyperendemic form in all SE Asia and Near Melanesia. Why? No idea. While the sampling is low density, it does seem like most relevant areas have been tested (map a), including Melanesia, Australian Aborigines, Indonesia and even Andaman.

So why these irregularities? Which are the founder effects implied? One can imagine that the northernmost historical malaria areas were free from the parasite in the Ice Age, but surely this was not the case of the Asian tropical belt. Did some sort of lifestyle, like choosing to dwell where marine breeze kept mosquitoes at bay (a usual common sense practice in tropical coasts as far as I know) help Eastern Eurasian founders prevent this disease, making the allele unnecessary? Was instead the HbS allele "stored" (by founder effect) in some South Asian demographic reservoir (and only there), gradually expanding to some nearby malaria affected areas but never participating of the colonization of the Far East by mere chance? 

What about the West, where the HbS allele is also mostly absent? Here at least one could argue that malaria was probably absent in the Pleistocene, so the HbS allele was logically selected against (even heterozygous types have some lesser disadvantages if malaria is not present to compensate for them).

It is a single SNP (rs334) which encodes all this matter, so it is not possible to trace it phylogenetically in any way.

Intriguing in any case.

Eastern Pygmies are not L1

Just a brief note to account for a paper to which I do not have access to but that says openly in the abstract that mtDNA lineages of Western and Eastern Pygmies are different.

It says that, while West Pygmies are essentially in the L1c haplogroup, Eastern Pygmies are instead in the L0a, L2 and L5 clades.

Chiara Battinin et al., Insights into the demographic history of African Pygmies from complete mitochondrial genomes. Molecular Biology and Evolution 2010. Pay per view.

Abstract

Pygmy populations are among the few hunter-gatherers currently living in sub-Saharan Africa and are mainly represented by two groups, Eastern and Western, according to their current geographical distribution. They are scattered across the Central African belt and surrounded by Bantu-speaking farmers, with whom they have complex social and economic interactions. To investigate the demographic history of Pygmy groups, a population approach was applied to the analysis of 205 complete mitochondrial DNA (mtDNA) sequences from ten central African populations. No sharing of maternal lineages was observed between the two Pygmy groups, with haplogroup L1c being characteristic of the Western group, but most of Eastern Pygmy lineages falling into sub-clades of L0a, L2a and L5. Demographic inferences based on Bayesian coalescent simulations point to an early split among the maternal ancestors of Pygmies and those of Bantu-speaking farmers (∼70,000 ya, years ago). Evidence for population growth in the ancestors of Bantu-speaking farmers has been observed, starting ∼65,000 ya, well before the diffusion of Bantu languages. Subsequently, the effective population size of the ancestors of Pygmies remained constant over time and ∼27,000 ya, coincident with the Last Glacial Maximum, Eastern and Western Pygmies diverged, with evidence of subsequent migration only among the Western group and the Bantu-speaking farmers. Western Pygmies show signs of a recent bottleneck 4,000 – 650 ya, coincident with the diffusion of Bantu languages, while Eastern Pygmies seem to have experienced a more ancient decrease in population size (20,000 - 4,000 ya). In conclusion, the results of this first attempt at analysing complete mtDNA sequences at the population level in sub-Saharan Africa not only support previous findings but also offer new insights into the demographic history of Pygmy populations, shedding new light on the ancient peopling of the African continent.

Found at Dienekes'.

Related posts at Leherensuge (my old blog):

• The early expansion of H. sapiens in Africa (mtDNA)
• Study suggests single origin for Pygmies (notice that both populations are clearly different already at K=3 anyhow)

Solutrean-style retouch 75,000 years ago in South Africa

Blombos point

Since I started reading about the MSA (Middle Stone Age, the main African Middle Paleolithic stone industry) I have been under the impression that it had Solutrean affinities.

Well, now it is confirmed that at least some MSA crafters, those from Blombos Cave, South Africa, effectively used this technique some 35,000 years before it was known in Europe.

Vincent Mourre et al. Early Use of Pressure Flaking on Lithic Artifacts at Blombos Cave, South Africa. Science 2010. Pay per view.

Abstract

Pressure flaking has been considered to be an Upper Paleolithic innovation dating to ~20,000 years ago (20 ka). Replication experiments show that pressure flaking best explains the morphology of lithic artifacts recovered from the ~75-ka Middle Stone Age levels at Blombos Cave, South Africa. The technique was used during the final shaping of Still Bay bifacial points made on heat-treated silcrete. Application of this innovative technique allowed for a high degree of control during the detachment of individual flakes, resulting in thinner, narrower, and sharper tips on bifacial points. This technology may have been first invented and used sporadically in Africa before its later widespread adoption.

Very few stones types (obsidian, jasper, high quality flint) can be retouched this way without previous thermal modification (heating the stone appropriately). This was the technique used at Pinnacle Point, not far from Blombos in that very same time. The technological sophistication is such that it has been compared to metallurgy.

While Pinnacle point offered the first evidence of stone preparation through heating in order to improve knapping, Blombos has the first one of pressure retouch. Other evidence of the so-called modern behavior (symbolism, art, etc.) is also abundant in the South African MSA. Even food processing is known from that time in nearby Mozambique.

Source: Science Daily.


Solutrean points (or casts):

< From Don's Maps:  

A cast of a Solutrean "laurel leaf" spear point, over 13 inches long. These delicate and beautiful implements were prepared by delicate flaking across the surface. Many are so large and delicate that they could never have been actually used, and may have been status objects.

Photo: Man before history by John Waechter

< From Lithic Casting Lab:

VOLGU LAUREL-LEAF POINTS (CASTS) - SOLUTREAN PERIOD

LE VOLGU - EASTERN FRANCE - UPPER PALEOLITHIC PERIOD

Francois Bordes wrote that "The majority of these specimens (Volgu cache) were chipped by direct percussion; but for the finer ones, indirect percussion or pressure has been used." Jacques Bordaz wrote that "The obvious fragility of some of the specimens (Volgu cache) suggest rather a ritual use, or perhaps they were simply examples of some knapper's bravura."

< From Wikipedia.

A more complete toolkit from Solutré-Pouilly.

Another culture that used the same technique later on was Clovis culture in Holocene North America.