Ariets Research Blog

June 28, 2009

MtDNA analysis of human remains from the Yuansha site in Xinjiang, China

Filed under: -Tocharians, Genetics — Ariets @ 10:41 pm

Abstract The Yuansha site is located in the center of the Taklimakan Desert of Xinjiang, in the southern Silk Road region. MtDNA was extracted from fifteen human remains excavated from the Yuansha site, dating back 2,000–2,500 years. Analysis of the phylogenetic tree and the multidimensional scaling (MDS) reveals that the Yuansha population has relatively close relationships with the modern populations of South Central Asia and Indus Valley, as well as with the ancient population of Chawuhu.

Source: link.

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Relationship of cranial robusticity to cranial form, geography and climate in Homo sapiens

Filed under: Genetics, Physical anthropology — Ariets @ 7:39 am

Abstract: Variation in cranial robusticity among modern human populations is widely acknowledged but not well-understood. While the use of robust cranial traits in hominin systematics and phylogeny suggests that these characters are strongly heritable, this hypothesis has not been tested. Alternatively, cranial robusticity may be a response to differences in diet/mastication or it may be an adaptation to cold, harsh environments. This study quantifies the distribution of cranial robusticity in 14 geographically widespread human populations, and correlates this variation with climatic variables, neutral genetic distances, cranial size, and cranial shape. With the exception of the occipital torus region, all traits were positively correlated with each other, suggesting that they should not be treated as individual characters. While males are more robust than females within each of the populations, among the independent variables (cranial shape, size, climate, and neutral genetic distances), only shape is significantly correlated with inter-population differences in robusticity. Two-block partial least-squares analysis was used to explore the relationship between cranial shape (captured by three-dimensional landmark data) and robusticity across individuals. Weak support was found for the hypothesis that robusticity was related to mastication as the shape associated with greater robusticity was similar to that described for groups that ate harder-to-process diets. Specifically, crania with more prognathic faces, expanded glabellar and occipital regions, and (slightly) longer skulls were more robust than those with rounder vaults and more orthognathic faces. However, groups with more mechanically demanding diets (hunter-gatherers) were not always more robust than groups practicing some form of agriculture. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc.

Source: link.

June 8, 2009

Y-STR variation among Slavs: evidence for the Slavic homeland in the middle Dnieper basin

Filed under: -Slavs, Genetics, Indo-Europeans — Ariets @ 6:25 pm

Quite old stuff.

Abstract: A set of 18 Y-chromosomal microsatellite loci was analysed in 568 males from Poland, Slovakia and three regions of Belarus. The results were compared to data available for 2,937 Y chromosome samples from 20 other Slavic populations. Lack of relationship between linguistic, geographic and historical relations between Slavic populations and Y-short tandem repeat (STR) haplotype distribution was observed. Two genetically distant groups of Slavic populations were revealed: one encompassing all Western-Slavic, Eastern-Slavic, and two Southern-Slavic populations, and one encompassing all remaining Southern Slavs. An analysis of molecular variance (AMOVA) based on Y-chromosomal STRs showed that the variation observed between the two population groups was 4.3%, and was higher than the level of genetic variance among populations within the groups (1.2%). Homogeneity of northern Slavic paternal lineages in Europe was shown to stretch from the Alps to the upper Volga and involve ethnicities speaking completely different branches of Slavic languages. The central position of the population of Ukraine in the network of insignificant AMOVA comparisons, and the lack of traces of significant contribution of ancient tribes inhabiting present-day Poland to the gene pool of Eastern and Southern Slavs, support hypothesis placing the earliest known homeland of Slavs in the middle Dnieper basin.

Source: Springerlink (fulltext).

June 6, 2009

Archaelogical and anthropological study of the gaves of Gara Banca – Sapte case (the counte of Vaslui)

Filed under: Physical anthropology — Ariets @ 12:08 pm

The archaeological diggings performed in the village of Banca – Sapte Case (the country of Vaslui) revealed 6 inhumation gaves, dated according to the analysis of the funeral inventory – in different periods of time…

To download it, click here.

June 2, 2009

Ancient mtDNA and craniometric evolution of Amerindians

Filed under: America — Ariets @ 6:23 pm

Oryginal post come from Dienekes Pontikos blog.

This paper shows that while the mtDNA gene pool of Amerindians did not undergo substantial change since the Holocene (haplogroups B, C, D were detected in the ancient samples, all of them common today), their cranial morphology changed from a more generalized to a more Mongoloid pattern.

In my opinion, the fact that Amerindians evolved in a Mongoloid direction may suggest one of three things:

  1. proto-Mongoloid traits were present as tendencies in the founding population, and they evolved in parallel in the Americas and in East Asia
  2. proto-Mongoloid traits were absent in the founding population, and they evolved independently in the Americas
  3. proto-Mongoloid traits were absent in the founding population, but they were added by limited gene flow from Asia

Even in Asia itself, except for isolated finds in Siberia, the first full-blown Mongoloids emerge in the Holocene. The Mongoloid type even spread to the south of the continent, which was formerly occupied by populations more similar to Australo-Melanesians.

Why the type became so successful remains to be seen; adaptive explanations for a rounder skull, flatter face, and heavy eyelids have been proposed as responses to extreme arctic cold, but why would similar phenotypes be selected for in regions of less extreme climate?

Sexual selection might play a role, although it would be difficult to establish over such a large area.

My guess is that various aspects of the Mongoloid pattern existed in low frequency or as isolated tendencies across East Eurasia and America. As populations grew during the Holocene, these traits spread in a wider range. Naturally, in the periphery, their blending was incomplete, with different quasi-Mongoloid types emerging there, e.g., prominent-nosed, round-headed Amerindians vs. flat-nosed, long-headed Proto-Uralics.

Thus, ancestral Amerindians either already had, or later received -by limited gene flow- a set of Mongoloid traits from Asia, which were selected for the same reasons as they did in Asia, but the “bottleneck” of the Bering did not allow them to receive the full package of traits.

PLoS ONE doi:10.1371/journal.pone.0005746

Discrepancy between Cranial and DNA Data of Early Americans: Implications for American Peopling

S. Ivan Perez et al.

Abstract

Currently, one of the major debates about the American peopling focuses on the number of populations that originated the biological diversity found in the continent during the Holocene. The studies of craniometric variation in American human remains dating from that period have shown morphological differences between the earliest settlers of the continent and some of the later Amerindian populations. This led some investigators to suggest that these groups—known as Paleomericans and Amerindians respectively—may have arisen from two biologically different populations. On the other hand, most DNA studies performed over extant and ancient populations suggest a single migration of a population from Northeast Asia. Comparing craniometric and mtDNA data of diachronic samples from East Central Argentina dated from 8,000 to 400 years BP, we show here that even when the oldest individuals display traits attributable to Paleoamerican crania, they present the same mtDNA haplogroups as later populations with Amerindian morphology. A possible explanation for these results could be that the craniofacial differentiation was a local phenomenon resulting from random (i.e. genetic drift) and non-random factors (e.g. selection and plasticity). Local processes of morphological differentiation in America are a probable scenario if we take into consideration the rapid peopling and the great ecological diversity of this continent; nevertheless we will discuss alternative explanations as well.
Source: Link

Русская Антропология (russian)

Check out Nicola_Canadian* website on typological concepts of physical anthropology, mixed with some genetics and linguistics et cetera. Nice, but don’t take it seriously to much.

Link

*he’s known on some boards that mention anthropology, ethnology and stuff (like old HBF, Anthroforum, Slavanthro (?) and some others).

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