The Duchy of Brabant was a historical region in the Low Countries between the 12th and 18th century and consisted of a present-day Dutch province and three contemporary Belgian provinces together with the Brussels-Capital Region. The total area is 14.425km2 with approximately 150 km between the two most remote places in Brabant. The main reason for selecting this region was the ability to obtain reliable genealogical data of the patrilineal line for each of the numerous donors living together on a small geographical scale.
The authors typed 37 Y-STRs, and 103 Y-SNPs. They write:
All individuals were correctly assigned to the main haplogroups using the Whit Atheys’ Haplogroup Predictor. In total, eight main haplogroups were observed with almost 85% of the samples belonging to haplogroup R(63%) and I(21%)(Table 1). On the lowest observed level of the phylogenetic tree 32subhaplogroups were found in the dataset, whereby nearly 70% of all samples belonged to only four subhaplogroups: R1b1b2a1(R-U106), R1b1b2a2* (R-P312*), R1b1b2a2g(R-U152) andI1*(I-M253*)
They found star-patterns in all their subhaplogroups, but uncovered some structure in their J2a* (J-M410*) chromosomes. Youngest expansion ages "were observed for E1b1b1a2(E-V13) and I1*(I-M253*), respectively 4182–5855 and 4531–6344 years ago."
a strong downward trend in the frequency of haplogroup R was observed from North to South (Table 1; Fig. S5). The difference in the frequency of R haplogroups was circa 10% between the most northern and southern part, mainly due to the downward frequency of R1b1b2a1(R-U106).The European-wide distribution of R-U106 suggests to me that it was a Germanic lineage.
Moreover, it was even possible to detect further substructuring within subha-
plogroup J2a*(J-M410*)based on the network analysis of all single-allele Y-STR haplotypes. Nevertheless, it was remarkable that the network analyses could not differentiate all observed subhaplogroups within R1b1b2(R-M269) and I2b(I-M223). This might be due to the relatively young age of these specific subhaplogroups making it impossible to differentiate these groups based on the Y-STRs.
The extraordinary success of these subhaplogroups is one of the most interesting questions: natural selection, or demographic dominance of a recently formed population group storming Western Europe by force of numbers? Ancient Y-DNA urgently needed...
The occurrence of haplogroup Q1 in 2.6% at Kempen, and 1.59% at Mechelen is an oddity of the findings that might merit further study.
In short this might be called a "model study" of Y-chromosome variation, due to the large number of individuals (477) and markers tested.
Forensic Sci Int Genet. 2010 Oct 29. [Epub ahead of print]
Micro-geographic distribution of Y-chromosomal variation in the central-western European region Brabant.
Larmuseau MH, Vanderheyden N, Jacobs M, Coomans M, Larno L, Decorte R.
One of the future issues in the forensic application of the haploid Y-chromosome (Y-chr) is surveying the distribution of the Y-chr variation on a micro-geographical scale. Studies on such a scale require observing Y-chr variation on a high resolution, high sampling efforts and reliable genealogical data of all DNA-donors. In the current study we optimised this framework by surveying the micro-geographical distribution of the Y-chr variation in the central-western European region named Brabant. The Duchy of Brabant was a historical region in the Low Countries containing three contemporary Belgian provinces and one Dutch province (Noord-Brabant). 477 males from five a priori defined regions within Brabant were selected based on their genealogical ancestry (known pedigree at least before 1800). The Y-haplotypes were determined based on 37 Y-STR loci and the finest possible level of substructuring was defined according to the latest published Y-chr phylogenetic tree. In total, eight Y-haplogroups and 32 different subhaplogroups were observed, 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 detected between the Dutch (Noord-Brabant) vs. the Flemish regions based on the differences in (sub)haplogroup frequencies but not based on Y-STR variation within the main subhaplogroups. A clear gradient was found with higher frequencies of R1b1b2 (R-M269) chromosomes in the northern vs. southern regions, mainly related to a trend in the frequency of R1b1b2a1 (R-U106).