AAPA 2013 abstracts

AAPA 2013 abstracts

The program of the 2013 meeting of the American Association of Physical Anthropologists is now online (pdf). As always, there is plenty of interest here, so I'll just highlight a few titles that caught my eye; feel free to add more in the comments.


Neolithic human mitochondrial haplogroup H genomes and the genetic origins of Europeans.

Haplogroup (hg) H dominates present-day Western European mitochondrial (mt) DNA variability (>40%), yet was less prevalent amongst early Neolithic farmers (~19%) and virtually absent in Mesolithic hunter-gatherers. To investigate this haplogroup’s significance in the maternal population history of Europeans we employed novel techniques such as DNA immortalization and hybridization-enrichment to sequence 39 hg H mt genomes from ancient human remains across a transect through time in Neolithic Central Europe. The results of our population genetic analyses reveal that the current patterns of diversity and distribution of hg H were largely established during the Mid-Neolithic, but with substantial genetic contributions from subsequent pan-European cultures such as the Bell Beakers, which expanded out of Iberia in the Late Neolithic (~2800 BC). Using a strict diachronic approach allowed us to reconcile ‘real-time’ genetic data from the most common European mtDNA hg with cultural changes that took place between the Early Neolithic (~5450 BC) and Bronze Age (~2200 BC) in Central Europe. This revealed the Late Neolithic (2800-2200 BC) as a dynamic period that profoundly shaped the genetic landscape of modern-day Europeans. Furthermore, linking ancient hg H genome sequences to specific points in time by using radiocarbon dates as tip calibrations allowed us to reconstruct a precise lineage history of hg H and to calculate a mutation rate 45% higher than traditional estimates based on the human/chimp split.

Preliminary research on hereditary features of Yinxu Population.

... The 37 individuals sampled in this study have been discovered in middle to small size burials, and therefore constitute a representative sample to study Yinxu commoners’ society. Mitochondrial DNA analysis showed that the Yinxu population included the haplogroups D, G, A, C, Z, M10, M*, B, F and N9a. According to the analysis of molecular variance, the distribution frequency and the rare published data, the Yinxu population shows a closest genetic affinity with the populations of Dadianzi and Zhukaigou early Bronze Age sites (Inner Mongolia), but a more distant relation to the historical period populations. The Yinxu population is also very similar to the modern northern Han Chinese. ... 

Investigating lactase persistence in a Medieval German cemetery: A step towards understanding the rise of the European lactase persistence polymorphism (-3910C/T).

Previous ancient DNA-based studies on the Neolithic found that the incidence of LP falls below detection levels in most regions. Our research shows that between the Neolithic and Medieval periods, the frequency of LP rose from near 0% to over 50%. Also, given that the frequency of LP genotypes in modern-day Germany is estimated at 78.5%, our results indicate that rather than being stable by the Medieval period, the lactase persistent genotype has continued to increase in frequency over the last 1000 years. This new evidence sheds light on the dynamic evolutionary history of the European lactase persistent trait and its global cultural implications.

 New Neanderthal remains from Kalamakia cave, Mani peninsula, Southern Greece.

Peeling back the layers: additional evidence for the date of the Petralona skull (Homo heidelbergensis), Greece.

,.. We conclude that there is no white sinter deposited directly on the skull and therefore the initial date of the skull given by Henning et al. and Grun’s revised date of ca. 200 ka are correct.

Analysis of archaic introgression in Ötzi the Tyrolean Iceman, a 5300 year-old prehistoric modern human.

... We carried out a series of comparisons to address these questions. By examining the Neandertal similarity of individuals from the 1000 Genomes Project, we have substantially expanded the sample of Neandertal-human comparisons. We also examined the genome of the Tyrolean Iceman, a European from approximately 5300 years ago. This is the first comparison of Neandertal genomes to the genome of a prehistoric modern human individual.

A quantitative approach for late Pleistocene hominin brain size.

... The results of our study show that Neanderthals have smaller brains than the Pleistocene AMH despite the fact that the latter are smaller in body mass. However, the Holocene AMH (7 populations) have smaller brain sizes than those of Neanderthals. ...

Re-evaluating the functional and adaptive significance of Neandertal nasofacial anatomy.

... Among Middle and Late Pleistocene Homo, there is evidence that nasal morphology varies with climate, albeit within an archaic architectural nasofacial framework. Neandertal internal nasal dimensions are greater in both height and length than archaic humans from sub-Saharan Africa. Furthermore, while other aspects of the nose are relatively broad, superior internal breadth dimensions in Neandertals are narrowed relative to sub-Saharan archaics. These differences parallel those seen in modern humans, indicating that Neandertals had an increased capacity for nasal heat and moisture exchange over their African counterparts and thus exhibit clear evidence for cold-climate adaptation.

The case for earlier Out-of-Africa (Boivin et al. 2013)

The case for earlier Out-of-Africa (Boivin et al. 2013)

An informative review critical of the ~60kya coastal-Out-of-Africa hypothesis. On the left, the authors' estimate of the distribution of hominin groups during MIS5.

From the paper:

Another under-appreciated issue is the anomalous nature of the genetic evidence for a rapid spread of modern humans from Africa to Asia. Echoing the fossil date anomaly, the mtDNA branch lengths for sampled populations are longest for those which are farthest east, in Near Oceania, and shortest in the Asian areas that would have been encountered first (Merriwether et al., 2005; Oppenheimer, 2009). The real problem, however, is that the variation in branch lengths suggests that a single genotype engaged in the expansion actually existed for 30 ka, which does not support a rapid expansion. The anomaly can be explained by what we call an an ‘M buffer’ effect (see Supplementary material A) which implies that the branch ages we observe are considerable underestimates of the time of arrival of the genotype to these areas. Such anomalously long-lived genotypes have been directly observed through ancient DNA in species such as the Iberian lynx (Dalen et al., 2011).

and:

We have focused here on the possibility that the modern human exit recorded by fossil evidence in the Levant in MIS 5 does not represent a failed dispersal, and that in fact our species was not only in the Levant but also the Arabian peninsula during this marine isotope stage, and spread to India before the Toba eruption at 74 ka (Petraglia et al., 2007). Another valid hypothesis we do not explore here is that H. sapiens was able to leave Africa in MIS 6 via a grassland corridor (Frumkin et al., 2011; see also Scally and Durbin, 2012). Yet another is that our species dispersed out of Africa shortly after its first appearance c. 195 ka, in MIS 7 (Dennell and Roebroeks, 2005: 1102). One other possibility is that there were several, separate dispersals of our species out of Africa (Dennell and Petraglia, 2012). At the same time, we acknowledge that major demographic changes occurred in MIS 4 and MIS 3, perhaps explaining the relatively young mtDNA coalescence age in living populations. The increasing evidence for complexity as well as the clear patterns of bias for all records, whether archaeological, fossil or genetic, suggests the need for an open mind to multiple scenarios for Out of Africa, as well as for more rather than less complex models of H. sapiens dispersal across Eurasia.

Quaternary International doi:10.1016/j.quaint.2013.01.008

Human Dispersal Across Diverse Environments of Asia during the Upper Pleistocene

Nicole Boivin et al.

The initial out of Africa dispersal of H. sapiens, which saw anatomically modern humans reach the Levant in Marine Isotope Stage 5, is generally regarded as a ‘failed dispersal’. Fossil, archaeological and genetic findings are seen to converge around a consensus view that a single population of H. sapiens exited Africa sometime around 60 thousand years ago (ka), and rapidly reached Australia by following a coastal dispersal corridor. We challenge the notion that current evidence supports this straightforward model. We argue that the fossil and archaeological records are too incomplete, the coastal route too problematic, and recent genomic evidence too incompatible for researchers not to remain fully open to other hypotheses. We specifically explore the possibility of a sustained exit by anatomically modern humans, drawing in particular upon palaeoenvironmental data across southern Asia to demonstrate its feasibility. Current archaeological, genetic and fossil data are not incompatible with the model presented, and appear to increasingly favour a more complex out of Africa scenario involving multiple exits, varying terrestrial routes, a sub-divided African source population, slower progress to Australia, and a degree of interbreeding with archaic varieties of Homo.

Link

Climate and history (in Eastern Europe)

Climate and history (in Eastern Europe)

PNAS doi: 10.1073/pnas.1211485110

Filling the Eastern European gap in millennium-long temperature reconstructions

Ulf Büntgen et al.

Tree ring–based temperature reconstructions form the scientific backbone of the current global change debate. Although some European records extend into medieval times, high-resolution, long-term, regional-scale paleoclimatic evidence is missing for the eastern part of the continent. Here we compile 545 samples of living trees and historical timbers from the greater Tatra region to reconstruct interannual to centennial-long variations in Eastern European May–June temperature back to 1040 AD. Recent anthropogenic warming exceeds the range of past natural climate variability. Increased plague outbreaks and political conflicts, as well as decreased settlement activities, coincided with temperature depressions. The Black Death in the mid-14th century, the Thirty Years War in the early 17th century, and the French Invasion of Russia in the early 19th century all occurred during the coldest episodes of the last millennium. A comparison with summer temperature reconstructions from Scandinavia, the Alps, and the Pyrenees emphasizes the seasonal and spatial specificity of our results, questioning those large-scale reconstructions that simply average individual sites.

Link

Body form variation of prehistoric Jomon (Fukase et al. 2012)

Body form variation of prehistoric Jomon (Fukase et al. 2012)

Am J Phys Anthropol DOI: 10.1002/ajpa.22112

Geographic variation in body form of prehistoric Jomon males in the Japanese archipelago: Its ecogeographic implications 

Hitoshi Fukase et al.

Diversity of human body size and shape is often biogeographically interpreted in association with climatic conditions. According to Bergmann's and Allen's rules, populations in regions with a cold climate are expected to display an overall larger body and smaller/shorter extremities than those in warm/hot environments. In the present study, the skeletal limb size and proportions of prehistoric Jomon hunter-gatherers, who extensively inhabited subarctic to subtropical areas in the ancient Japanese archipelago, were examined to evaluate whether or not the inter-regional differences follow such ecogeographic patterns. Results showed that the Jomon intralimb proportions including relative distal limb lengths did not differ significantly among five regions from northern Hokkaido to the southern Okinawa Islands. This suggests a limited co-variability of the intralimb proportions with climate, particularly within genealogically close populations. In contrast, femoral head breadth (associated with body mass) and skeletal limb lengths were found to be significantly and positively correlated with latitude, suggesting a north-south geographical cline in the body size. This gradient therefore comprehensively conforms to Bergmann's rule, and may stem from multiple potential factors such as phylogenetic constraints, microevolutionary adaptation to climatic/geographic conditions during the Jomon period, and nutritional and physiological response during ontogeny. Specifically, the remarkably small-bodied Jomon in the Okinawa Islands can also be explained as an adjustment to subtropical and insular environments. Thus, the findings obtained in this study indicate that Jomon people, while maintaining fundamental intralimb proportions, displayed body size variation in concert with ambient surroundings.


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The Finno-Ugrian Suicide Hypothesis

The Finno-Ugrian Suicide Hypothesis

This study discovers that suicide rates in Europe are strongly correlated with geography. Countries with high suicide rates form a belt from Finland to Austria which corresponds with the genetic zone of cold adaptation and ancient Uralic language dispersion. The authors suggest that genetic risk factors in this region are responsible for high suicide rates.

Percept Mot Skills. 2003 Oct;97(2):401-6.

The Finno-Ugrian suicide hypothesis: variation in European suicide rates by latitude and longitude.
Voracek M et al.

The marked variation regarding the suicide rate in 34 European countries is well described by regressing the national suicide rate on the capital cities' latitudes and on an interaction term of squared latitude multiplied with longitude. The interaction term explains 40.8% and 29.1% of men's and women's suicide rate, respectively, and latitude explains a further significant increment of 10.9% and 10.6% variance of men's and women's suicide rate, respectively. This regression model quantifies the Finno-Ugrian suicide hypothesis of Kondrichin and of Marusic and Farmer. The European countries highest in suicide rate constitute a contiguous, J-shaped belt, spanning from Finland to Austria. This area maps onto the second principal component identified for European gene distribution, representing ancestral adaptation to cold climates and the Uralic language dispersion. Thus, population differences in genetic risk factors may account for the spatial pattern in European suicide rates.

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Spread of the Scythians after c. 850BC

Spread of the Scythians after c. 850BC

A new paper proposes that reduced solar activity after 850BC resulted in the transformation of formerly desert-like regions into herbivore-friendly wet steppes. According to this theory, the Scythian culture expanded after this time, taking advantage of the newly created steppe regions.

Journal of Archaeological Science
Article in Press, Corrected Proof
doi:10.1016/j.jas.2004.05.004

Climate change and the expansion of the Scythian culture after 850 BC: a hypothesis
B. van Geel et al.

Abstract

In south-central Siberia archaeological evidence suggests an acceleration of cultural development and an increase in the density of nomadic populations around 850 BC. We hypothesize a relationship with an abrupt climatic shift towards increased humidity caused by a decline of solar activity. Areas that initially may have been hostile semi-deserts changed into attractive steppe landscapes with a high biomass production and high carrying capacity. Newly available steppe areas could be invaded by herbivores, making them attractive for nomadic tribes. The central Asian horse-riding Scythian culture expanded, and an increased population density was a stimulus for westward migration towards southeastern Europe.

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