The R1b-CTS4466 Plus Project has been established to research the parameters of this major subclade which features strongly in the south of Ireland, but is found as well in other areas of the Isles, including some in the west of Ireland, Wales, western England, an apparent branch in Northern Ireland and Scotland and a few continentals. We hope through our investigations to establish the hierarchy of the various SNPs currently known to be associated with the Irish Type II haplotype and discover more about the branches that are there amidst the significant number of men carrying this genetic signature. As these branches continue to be identified, we will be better able to determine the possible origins of this prominent subclade centred in the south of Ireland.