Both STRUCTURE and principal component (PC) analyses showed the largest principal component differentiated northern from southern European ancestry.
A second PC further separated Italian, Spanish, and Greek from Ashkenazi ancestry as well as distinguishing among northern European populations.
In separate analyses of northern European participants … relationships were discerned showing a west to east gradient.
Application of this substructure information was critical … for rheumatoid arthritis in European Americans to reduce false positive signals.
… two sets of European substructure ancestry informative markers (ESAIM). The results … show that this information can be used …in association testing of candidate genes and in replication studies of WGA scans.