Within R-L21, the FTDNA system flags the profile as potentially belonging to the R-DF21 subclade, which carries its own geographic signal. R-DF21 shows a diffuse distribution across Ireland, with the Z3000 branch — known as Clan Colla — concentrated specifically in southern Ulster. Antrim and Tyrone both fall within that Ulster corridor. This does not prove either county. It narrows the field.