August 19, 2007

Dispersal of haplogroup N from Siberia into Eastern Europe

J Hum Genet. 2007 Aug 17; [Epub ahead of print]

Y-chromosome haplogroup N dispersals from south Siberia to Europe.

Derenko M, Malyarchuk B, Denisova G, Wozniak M, Grzybowski T, Dambueva I, Zakharov I.

In order to reconstruct the history of Y-chromosome haplogroup (hg) N dispersals in north Eurasia, we have analyzed the diversity of microsatellite (STR) loci within two major hg N clades, N2 and N3, in a total sample of 1,438 males from 17 ethnic groups, mainly of Siberian and Eastern European origin. Based on STR variance analysis we observed that hg N3a is more diverse in Eastern Europe than in south Siberia. However, analysis of median networks showed that there are two STR subclusters of hg N3a, N3a1 and N3a2, that are characterized by different genetic histories. Age calculation of STR variation within subcluster N3a1 indicated that its first expansion occurred in south Siberia [approximately 10,000 years (ky)] and then this subcluster spread into Eastern Europe where its age is around 8 ky ago. Meanwhile, younger subcluster N3a2 originated in south Siberia (probably in the Baikal region) approximately 4 ky ago. Median network and variance analyses of STR haplotypes suggest that south Siberian N3a2 haplotypes spread further into Volga-Ural region undergoing serial bottlenecks. In addition, median network analysis of STR data demonstrates that haplogroup N2-A is represented by two subclusters, showing recent expansion times. The data obtained allow us to suggest Siberian origin of haplogroups N3 and N2 that are currently widespread in some populations of Eastern Europe.


August 15, 2007

The new Ming the Merciless

I haven't watched the new incarnation of Flash Gordon on SCI-FI Channel, but can anyone spot a difference between the Ming character from the 1930s serial and last FG movie and the newest one?

Hypothesis about the origins of hemochromatosis

Med Hypotheses. 2007 Aug 7; [Epub ahead of print]

Hemochromatosis: A Neolithic adaptation to cereal grain diets.

Naugler C.

The Neolithic period in Europe marked the transition from a hunter-gatherer diet rich in red meat to an iron-reduced cereal grain diet. This dietary shift likely resulted in an increased incidence of iron deficiency anemia, especially in women of reproductive age. I propose that hereditary hemochromatosis and in particular the common HFE C282Y mutation may represent an adaptation to decreased dietary iron in cereal grain-based Neolithic diets. Both homozygous and heterozygous carriers of the HFE C282Y mutation have increased iron stores and therefore possessed an adaptive advantage under Neolithic conditions. An allele age estimate places the origin of the HFE C282Y mutation in the early Neolithic period in Northern Europe and is thus consistent with this hypothesis. The lower incidence of this mutation in other agrarian regions (the Mediterranean and Near East) may be due to higher dietary intakes of the iron uptake cofactor vitamin C in those regions. The HFE C282Y mutation likely only became maladaptive in the past several centuries as dietary sources of iron and vitamin C improved in Northern Europe.


New YHRD release

An August 10 release of the YHRD - Y Chromosome Haplotype Reference Database.
Twenty populations were added or updated today: two Amerindian tribal populations from the Formosa province in Argentina (Pilaga, Toba), one from Venezuela (Caracas), two from provinces in Colombia (Boyaca, Cundinamarca), three from Siberian nomad populations (Western and Central Evens, Iengra Evenks), one from Belarus (Pinsk), three from Ukraine (Kiev, Lviv, Lugansk), three populations from Capetown in South Africa, three from Ravenna, Rimini and Val Marecchia in Italy, one from Hungary, one from Peru and one from Oran in Algeria.

August 04, 2007

Mating patterns amongst Siberian reindeer hunters

Am J Phys Anthropol. 2007 Jul;133(3):1013-27

Mating patterns amongst Siberian reindeer herders: inferences from mtDNA and Y-chromosomal analyses.

Pakendorf B, Novgorodov IN, Osakovskij VL, Stoneking M.

The Evenks and Evens, who speak closely related languages belonging to the Northern Tungusic branch of the Tungusic family, are nomadic reindeer herders and hunters. They are spread over an immense territory in northeastern Siberia, and consequently different subgroups are in contact with diverse peoples speaking Samoyedic, Turkic, Mongolic, Chukotka-Kamchatkan, and Yukaghir languages. Nevertheless, the languages and culture of the Evenks and Evens are similar enough for them to have been classified as a single ethnic group in the past. This linguistic and cultural similarity indicates that they may have spread over their current area of habitation relatively recently, and thus may be closely related genetically. On the other hand, the great distances that separate individual groups of Evens and Evenks from each other might have led to preferential mating with geographic neighbors rather than with linguistically related peoples. In this study, we assess the correlation between linguistic and genetic relationship in three different subgroups of Evenks and Evens, respectively, via mtDNA and Y-chromosomal analyses. The results show that there is some evidence of a common origin based on shared mtDNA lineages and relatively similar Y-haplogroup frequencies amongst most of the Evenk and Even subgroups. However, there is little sharing of Y-chromosomal STR haplotypes, indicating that males within Evenk and Even subgroups have remained relatively isolated. There is further evidence of some female admixture in different Even subgroups with their respective geographic neighbors. However, the Tungusic groups, and especially the Evenks, show signs of genetic drift, making inferences about their prehistory difficult.


August 01, 2007

Y chromosomes of Guinea-Bissau

BMC Evol Biol. 2007 Jul 27;7(1):124. [Epub ahead of print]

Y-chromosomal diversity in the population of Guinea-Bissau: a multiethnic

Rosa A, Ornelas C, Jobling MA, Brehm A, Villems R.

ABSTRACT: BACKGROUND: The geographic and ethnolinguistic differentiation of many African Y-chromosomal lineages provides an opportunity to evaluate human migration episodes and admixture processes, in a pan-continental context. The
analysis of the paternal genetic structure of Equatorial West Africans carried out to date leaves their origins and relationships unclear, and raises questions about the existence of major demographic phenomena analogous to the large-scale
Bantu expansions. To address this, we have analysed the variation of 31 binary and 11 microsatellite markers on the non-recombining portion of the Y chromosome in Guinea-Bissau samples of diverse ethnic affiliations, some not studied before.
RESULTS: The Guinea-Bissau Y chromosome pool is characterized by low haplogroup diversity (D=0.470, sd 0.033), with the predominant haplogroup E3a*-M2 shared among the ethnic clusters and reaching a maximum of 82.2% in the Mandenka people. The Felupe-Djola and Papel groups exhibit the highest diversity of lineages and harbor the deep-rooting haplogroups A-M91, E2-M75 and E3*-PN2, typical of Sahel's more central and eastern areas. Their genetic distinction from other groups is
statistically significant (P=0.01) though not attributable to linguistic, geographic or religious criteria. Non sub-Saharan influences were associated with the presence of haplogroup R1b-P25 and particular lineages of E3b1-M78.
CONCLUSIONS: The predominance and high diversity of haplogroup E3a*-M2 suggests a demographic expansion in the equatorial western fringe, possibly supported by a local agricultural center. The paternal pool of the Mandenka and Balanta displays evidence of a particularly marked population growth among the Guineans, possibly reflecting the demographic effects of the agriculturalist lifestyle and their putative relationship to the people that introduced early cultivation practices
into West Africa. The paternal background of the Felupe-Djola and Papel ethnic groups suggests a better conserved ancestral pool deriving from East Africa, from where they have supposedly migrated in recent times. Despite the overall
homogeneity in a multiethnic sample, which contrasts with their social structure, minor clusters suggest the imprints of multiple peoples at different timescales: traces of ancestral inhabitants in haplogroups A-M91 and B-M60, today typical of
hunter-gatherers; North African influence in E3b1-M78 Y chromosomes, probably due to trans-Saharan contacts; and R1b-P25 lineages reflecting European admixture via the North Atlantic slave trade.