A set of 128 SNPs selected on the basis of informativeness (In) between four continental groups (European, Amerindian, West African and East Asian) passed our initial quality filters (see Methods). Analysis of genotypes using this informative marker set (designated 128 In4) was first evaluated using Fst as a general measure of the ability to separate continental population groups. The markers showed large Fst differences between the continental populations and relatively small differences within large groups of disparate individuals within these continental groups (Table 1). The South-Asian group, not used in the marker selection, showed substantial differences with the European group consistent with previous observations that this sub-continental group is distinct (Yang, et al., 2005). In addition, there was a larger intercontinental difference among the Amerindian groups as previously observed (Price, et al., 2007; Tian, et al., 2007).
