High resolution mapping of Y haplogroup G in Tyrol (Austria)

The distribution of Y-chromosomal haplogroup G2a (G-P15) in present-day paternal lineages in Tyrol (Austria) was analyzed by applying a high-density regional sampling scheme that also covered remote mountain areas. There is evidence from ancient genetic data for a high frequency of Y-chromosomal haplogroup G in prehistoric populations of Central Europe, whilst nowadays levels well below 10% are routinely observed. A population sample comprising ∼3700 specimens was analyzed for Y-chromosomal variation by genotyping Y-SNPs and Y-STRs. The set of binary markers included nine SNPs specific for sub-lineages of haplogroup G. The frequency of haplogroup G in 2379 unrelated men born in Tyrol amounted to 11.3%. Nearly all of these Y chromosomes belonged to haplogroup G2a. The main sub-haplogroup within G2a was defined by the SNP L497 (G2a3b1c) and reached a population frequency of 8.6%. Although this average level is higher than reported for other countries the geographical distribution of haplogroup G-L497 showed a differentiated pattern with a clustered distribution within some alpine valleys, where maxima above 40% were found. Both, the estimation of coalescent times and a principle coordinates analysis based on RST values derived from Y-STR haplotypes from different sub-regions of Tyrol revealed evidence for an old settlement history associated with Y chromosomes belonging to haplogroup G in the Tyrolean Alps.