Haplogroup R1b (R-M343) is the most frequently occurring Y-chromosome haplogroup in Western Europe and the most common haplogroup in the genetic genealogy databases.R1b1a2 (R-M269) is the dominant branch of R1b in Western Europe.When you take a standard Y-chromosome DNA test with a company such as Family Tree DNA you will be given a base haplogroup assignment such as R1b1a2 (R-M269).n November 2012 Tim Janzen analysed a file of 1089 SNP-tested R-U106 haplotypes and 701 SNP-tested R-P312 haplotypes. He found that the modal (most common) allele values at 37 markers were the same for both R-U106 and R-P312 with the exception of these markers: DYS390, DYS576 and CDYa.