There are now 138 men who have publicly released their SNP testing results which are positive for CTS4466 or a downstream marker. This marker (or one of it’s 17 known equivalents) emerged sometime between 89BC and 243AD from calculations done by the 4466 & South Irish base haplotype project. The marker’s true origin is a mystery but is most associated with the Eóganachta clan in southern Ireland.
As mentioned previously in this blog, Next Generation Sequencing methods on the Y chromosome have begun to subdivide this haplogroup. The linked document at the top of this post attempts to associate those divisions with unique STR signature. These signatures can be used to compare a known sample to determine if it would be advisable to test for one of the newly discovered SNPs like S1121, A195, or A151s. The suggested usage is to make sure the target STRs fall within the minimum and maximum values with no more than one location outside that range. Also take into account your distance away from the modal value and attempt to keep it within 20% number of test positions. The heuristic works reasonably well on older SNPs, but may need to be revised as the variants become younger.