#416160

Anonymous

Lusatian Sorbs (SB) and other Slavic ethnicities as target populations (PL, CZ, SK, SI, HR, BA, YU, RS, BG, MC, RU, UA).

Title: Genetic variation in the Sorbs of eastern Germany in the context of broader European genetic diversity (2011) by Veeramah et al.
Publisher: European Journal of Human Genetics (2011) 19, 995–1001;

Abstract

The Sorbs of Germany are considered as cultural and linguistic isolates and have recently been the focus of disease association mapping efforts. They are thought to have settled in their present location in eastern Germany after a westward migration from a largely Slavic-speaking territory during the Middle Ages. To examine Sorbian genetic diversity within the context of other European populations, we analyzed genotype data for over 30 000 autosomal single-nucleotide polymorphisms from over 200 Sorbs individuals. We compare the Sorbs with other European individuals, including samples from population isolates. Despite their geographical proximity to German speakers, the Sorbs showed greatest genetic similarity to Polish and Czech individuals, consistent with the linguistic proximity of Sorbian to other West Slavic languages. The Sorbs also showed evidence of subtle levels of genetic isolation in comparison with samples from non-isolated European populations. The level of genetic isolation was less than that observed for the Sardinians and French Basque, who were clear outliers on multiple measures of isolation. The finding of the Sorbs as only a minor genetic isolate demonstrates the need to genetically characterize putative population isolates, as they possess a wide range of levels of isolation because of their different demographic histories.

Population

A total of 996 Upper Sorbian speakers of the Catholic denomination were recruited from private practices in eight villages from Eastern Saxony. These individuals were initially thinned to a set consisting of 289 Sorbian individuals (124=male, 165=female), on the basis of the criteria that all four grandparents were described as Sorbian. We also conducted a more conservative filtering of these 289 individuals by a stricter IBD analysis that resulted in what would be considered a homogenous set of 178 unrelated Sorbs.

POPRES: genotype data for 1387 European individuals from the Population Reference Sample (POPRES) project
HGDP: genotype data for 140 European individuals from the Human Genome Diversity Project (HGDP) panel
LPZ – Leipzig sample
SB (Sorbs)
Russian_HGDP is from northern population in Archangel region
KS – Kosovo?

Method

Principal Component Analysis in Diagram 1 and 2; Fixation Index (Fst) in Diagram 3

PCA1 is on y axis and PCA2 is on x axis for two plots. Diagram 1: Boostrap analysis using POPRES/LPZ dataset merge based on sample's country of origin, Diagram 2 : Boostrap analysis without POPRES/HGDP dataset merge

Diagram 1

[IMG]http://img818.imageshack.us/img818/4917/sb1p.png” />

Diagram 2

[IMG]http://img836.imageshack.us/img836/756/sb2d.png” />

Diagram 3

[IMG]http://img521.imageshack.us/img521/9505/sb3b.png” />

Results

PCA analysis using the POPRES/HGDP merge. The bootstrap distribution of the median PC1–PC2 position of the Sorbs overlaps that of the Poles, demonstrating their genetic similarity, but was distinct from both the Germans and Czechs

Pairwise FST values were calculated between all populations with a sample size of 10 or greater.The Sorbs were generally found to be closer to Slavic- than Germanic-speaking population. Examining these distances in more detail showed the Sorbs to be closer to Czechs than Poles but this difference was not statistically significant when assessed by permutation (P=0.280).

When ancestry components were averaged within populations (Supplementary Figure 4), the Sorbs were somewhat more distinct from other populations. For K=2, 3 and 4, the Sorbs showed greatest similarity to Poles, followed by Czechs, Slovaks and the two German populations.