European cluster as including all those individuals with D2 < 84. We also confirmed that full siblings and DZ twins were never in separate clusters. After adding 1087 MZ cotwins, the final sample of 7702 individuals with European ancestry (91.6% of the total sample) included 101 who had missing self-reported ethnicity data and 46 whose ethnicity had been recorded as other than white (several of those cases were found to have been caused by data-entry errors).
