In a message dated 7/7/2011 6:48:39 P.M. Central Daylight Time, davidewing93@gmail.com writes: R:M222 is 'defined' on the basis of the presence of the SNP M222. The definition has nothing to do with STR testing; ie, it does not depend at all on testing the markers we construct modals with. Iain correctly points out that David Wilson first identified a STR profile he thought was characteristic of NW Ireland that eventually proved to be associated with R:M222, but I do not believe that Wilson was aware of the SNP at that time and I do not think he tested for it. I can only add the SNP had been known at the time in academic circles but not routinely tested for when David Wilson announced his finding of the NW Irish cluster. As I recall it was associated with sterility in some studies, since repudiated. David was the first of the cluster to get tested for the SNP though.