"Haploid DNA Markers in Forensic Genetics" 7th International Y Chromosome User Workshop and 4th International EMPOP meeting location:Charité, Berlin, Germany date:22-24 April 2010
A future issue in human phylogeography is surveying the distribution of genetic variation on a micro-geographic scale to identify key determinants of population structure in humans. An interesting region to investigate regional distribution of genetic variation is Belgium mainly due to the presence of a language border without physical barriers, the Romance-Germanic language border. To survey the origin and the evolutionary significance of this border, a micro-scaled biogeographical analysis will be performed with data from haploid markers and whole-genomic approaches. Here we want to present results of a first phase of this project, a study of the Y-chromosomal (Y-chr) variation in the Duchy of Brabant, a historical region in the Low Countries containing three contemporary Belgian provinces and the Dutch province of North Brabant. 477 males from five different regions within the Duchy of Brabant were selected based on their genealogical data (pedigree at least before 1800). For all participants, the finest level of substructuring are defined according to the latest published Y-chr phylogenetic tree, as well the Y-haplotypes are determined based on 37 Y-STR loci. The observed Y-chr variation is subdivided within eight Y-haplogroups and within 32 Y-subhaplogroups, whereby 70% of all participants belonged to only four subhaplogroups: R1b1b2a1 (R-U106), R1b1b2a2* (R-P312*), R1b1b2a2g (R-U152) and I1* (I-M253*). Significant micro-geographical differentiation within Brabant was observed between the Dutch province of North Brabant vs. the Flemish provinces based on the differences in (sub)haplogroup frequencies but not based on Y-haplotypes within the main subhaplogroups. A clear gradient was found with higher frequencies of R1b1b2 chromosomes in the northern vs. southern regions. The data will be extended by sampling campaigns of all regions in Belgium as well of the Grand Duchy of Luxemburg and French Flanders (France). This project will give more insights into regional distribution of genetic variation along language borders and will define new hypotheses on the role of cultural characteristics in human genetics.