January 30, 2012

AAPA 2012 abstracts (part 1)

Here are some interesting abstracts from the 81st Annual Meeting of the American Association of Physical Anthropologists.

Maternal marks of admixture in Cape Coloreds of South Africa.
Previous studies of genetic diversity have suggested that the Cape Coloureds of South Africa are a highly admixed population with genetic roots from indigenous African groups including Khoisans, and the later arrival of Bantu speaking Xhosa farmers. Further genetic contributions came during European colonization of South Africa, which added to the inclusion of largely male European markers to the gene pool. Slaves from Indonesia, Malaysia, Madagascar and India are also thought to have contributed to the genetic makeup of this ethnic group. This study examines the maternal contribution of each of these groups to the genetic diversity of the Cape Coloreds through sequencing of the hypervariable region I of the mitochondrial DNA and through restriction fragment length polymorphism.
A total of 123 individuals were examined for this study. High frequencies of haplogroups L1 and L2 were found at 81.3 percent in this group (100 of the 123 individuals), which indicates that this group has a large African contribution to its mitochondrial makeup. Restrictions of the major European haplogroups identified nine individuals, 7.3 percent of the sample, belonged to haplogroups I and J. Five individuals (4.1 percent of the sample) belonged to the superhaplogroup M, indicating that Asian slaves did contribute to the maternal gene pool. The majority of maternal lineages in this Cape Coloured sample are African in origin, with some European influence and a small contribution from Asian maternal lineages.

Ancient DNA reveals the population origin of the Eastern Xinjiang.
Connecting with the Turpan Basin, the Eurasia steppe and the Gansu Corridor, the Eastern region of Xinjiang has played a significant role in the history of human migration, cultural developments, and communications between the East and the West. The population origin, migration and integration of this region have attracted extensive interest among scientists.
In order to research the population origin and movement of the Eastern Xinjiang, genetic polymorphisms studies of the Hami population were conducted. The Hami site is located in the East of Tian-Moutain in Xinjiang, dating back to the Bronze-early Iron Age. Archaeological studies showed that the culture of the Hami site possessed features from both the East and the West. Ancient mtDNA analysis showed that A, C, D, F, G, Z and M7 of the Eastern maternal lines, and W, U2e, U4, and U5aof the Western maternal lines were identified. Tajimas’D test and mismatch distribution analysis show that the Hami population had experienced population expansion in recent time. The demographic analysis of haplogroups suggests that the populations of the Northwest China, Siberia and the Central Asia have contributed to the mtDNA gene pool of the Hami population.
Our study reveals the genetic structure of the early population in Eastern Xinjiang, and its relationships with other Eurasian populations. The results will provide valuable genetic information to further explore the population origin and migration of Xinjiang and Central Asia.

Analysis of Chuvash mtDNA points to Finno-Ugric origin.
A sample of 92 unrelated individuals from Chuvashia, Russia was sequenced for hypervariable region-I (HVR-I) of the mtDNA molecule. These data have been verified using RFLP analysis of the control region, revealing that the majority exhibit haplogroups H (31%), U (22%), and K (11%), which occur in high frequencies in western and northern Europe, but are virtually absent in Altaic or Mongolian populations. Multidimensional scaling (MDS) was used to examine distances between the Chuvash and reference populations from the literature. Neutrality tests (Tajima’s D (-1.43365) p<0.05, Fu’s FS (-25.50518) p<0.001) and mismatch analysis, which illustrates unimodal distribution, all suggest an expanding population.
The Chuvash speak a Turkic language that is not mutually intelligible to other extant Turkish groups, and their genetics are distinct from Turkic-speaking Altaic groups. Some scholars have suggested that they are remnants of the Golden Horde, while others have advocated that they are the products of admixture between Turkic and Finno-Ugric speakers who came into contact during the 13th century. Earlier genetic research using autosomal DNA markers indicated a Finno-Ugric origin for the Chuvash. This study examines uniparental mitochondrial DNA markers to better elucidate their origins. Results from this study maintain that the Chuvash are not related to Altaic or Mongolian populations along their maternal line, thus supporting the “Elite” hypothesis that their language was imposed by a conquering group —leaving Chuvash mtDNA largely of Eurasian origin. Their maternal markers appear to most closely resemble Finno-Ugric speakers rather than Turkic speakers.

An ancient DNA perspective on the Iron Age “princely burials” from Baden-Wurttemberg, Germany.
During the Iron Age in Europe, fundamental social principles such as age, gender, status, and kinship were thought to have played an important role in the social structure of Late Hallstatt and Early Latene societies. In order to address the question of kinship relations represented in the Iron Age “princely burials” that are characterized by their rich material culture, we carried out genetic analysis of individuals associated with the Late Hallstatt culture from Baden-Wurttemberg, Germany. Bone specimens of thirty-eight skeletal remains were collected from five sites including Asperg Grafenbuhl, Muhlacker Heidenwaldle, Hirschlanden, Ludwigsburg, and Schodeingen. Specimens were subjected to DNA extraction and amplification under strict criteria for ancient DNA analysis. We successfully obtained mitochondrial DNA (mtDNA) control region sequences from seventeen individuals that showed different haplotypes, which were assigned to nine haplogroups including haplogroups H, I, K, U5, U7, W, and X2b. Despite the lack of information from nuclear DNA to infer familial relations, information from the mtDNA suggests an intriguing genetic composition of the Late Hallstatt burials. In particular, twelve distinct haplotypes from Asperg Grafenbuhl suggest a heterogeneous composition of maternal lineages represented in the “princely burials”. The results from this study provide clues to the social structure reflected in the burial patterns of the Late Hallstatt culture and implications on the genetic landscape during the Iron Age in Europe.

Genetic snapshot from ancient nomads of Xinjiang.
Nomads of the Eurasian steppes are known to have played an important role in the transfer commodities and culture among East Asia, Central Asia, and Europe. However, the organization of nomadic societies and initial population genetic composition of nomads were still poorly understood because of few archaeological materials and written history.
In this study, the genetic snapshot of nomads was emerged by examining mitochondrial DNA and Y-chromosome DNA of 30 human remains from Heigouliang (HGL) site in the eastern of Xinjiang, which dated 2000 years ago and associated to the nomadic culture by archaeological studies. Mitochondrial DNA analysis showed that the HGL population included both East Eurasian haplogroups (A, C, D, G, F and Z) and West Eurasian haplogroups (H, K, J, M5 and H). The component of Eastern haplogroups is dominant. The distribution frequency and Fst values of Eastern haplogroups indicated the HGL population presented close genetic affinity to the nearby region modern populations of Gansu and Qinghai, while those of western haplogroups showed similar with Mongolia and Siberia populations. The results implied various maternal lineages were introduced into the HGL population. Regarding the Y chromosomal DNA analysis, nearly all samples belonged to haplogroup Q which is thought to be the mark of the Northern Asian nomads. We identified paternal kinship among three individuals at the same tomb by Y-STR marker.
Combined with archaeological and anthropological investigations, we inferred that the gene flow from the neighboring regions was possibly associated with the expansion of Xiongnu Empire.

Vikings, merchants and pirates at the top of the world: Y-chromosomal signatures of recent and ancient migrations in the Faroe Islands.
The Faroe Islands are a small archipelago in the North Atlantic Ocean. With a current population of approximately 48,000 individuals and evidence of high levels of genetic drift, the Faroese are thought to have remained highly homogeneous since the islands were settled by Vikings around 900CE. Despite their geographic isolation, however, there is historical evidence that the Faroese experienced sporadic contact with other populations since the time of founding. Contact with Barbary pirates in the seventeenth century is documented in the Faroes; there is also the possibility of modern migrations to work in the highly productive fishery. This study set out to distinguish the signal of the original founders from later migrants. Eleven Y-chromosomal STR markers were scored for 139 Faroese males from three geographically dispersed islands. Haplotypes were analyzed using Athey's method to infer haplogroup. Median-joining networks within haplogroups were constructed to determine the phylogenetic relationships within the Faroese and between likely parental populations—Danish, Irish, and Norwegians. Dispersal patterns of individuals around Faroese haplogroups suggest different times of haplotype introduction to the islands. The most common haplogroup, R1a, consists of a large node with a tight network of neighbor haplotypes, such that 68% of individuals are one or two mutational steps away. This pattern may represent the early founder event of R1a in the Faroes. Other distributions, especially of non-Scandinavian haplotypes, document more recent introductions to the islands. The overall pattern is one of a strong founder effect followed by minor instances of later migrations.

Date estimates for major mitochondrial haplogroups in Yemen.
Yemen occupies a key location as the first stop for anatomically modern humans on a theoretical southern migration route out of Africa. If modern humans did pass through Yemen during the first migrations out of Africa and if they left modern-day descendants, we would expect to see deep divergences in the Yemeni mitochondrial gene tree. Alternatively, if modern humans passed through Yemen but did not leave modern-day descendants or if Yemen was not on the path of these ancient migrations, we would expect more recent dates to be associated with Yemeni mitochondrial haplogroups.
Using 44 previously sequenced mitochondrial genomes as well as 24 newly sequenced mitochondrial genomes from samples collected throughout Yemen, several methods were used to estimate divergence dates of major Yemeni haplogroups including L2, M, R0a and HV. Specifically, phylogenetic trees were generated using MrBayes and maximum likelihood methods. Bayesian and ρ statistic based methods were used to estimate dates of Yemeni haplogroups and these dates were compared with each other, previously published dates for these haplogroups, approximate dates of climatic change that might be expected to correlate with population expansions, and estimates based on archaeological and paleontological evidence for the first migrations out of Africa. These comparisons are intended to cover the range of possible haplogroup divergence dates with respect to the history of early modern humans in southern Arabia.


pconroy said...

In terms of the Faroe Islands, it's known that the Irish were the first to settle there - see Diciul's works.

I would imagine that they would be overwhelmed by the later Vikings, and be a minor Y-DNA contributor of today's population, but it doesn't make sense that they would be later arrivals to the islands at all?!

pconroy said...

More info on Dicuil and Faroe Islands and Vikings - from the Smithsonian:


princenuadha said...

From the iron age German study,

"and implications on the genetic landscape during the Iron Age in Europe"

What does this mean?