To estimate genetic ancestry proportions for each subject, DNA samples were genotyped using a panel of 23 markers with high efficiency at clustering individuals into population subgroups (Smith et al., 2001; Yang et al., 2005). Short tandem repeat markers D1S252, D2S319, D12S352, D17S799, D8S272, D1S196, D7S640, D8S1827, D7S657, D22S274, D5S407, D2S162, D10S197, D11S935, D9S175, and D5S410 were selected from Applied Biosystems (AB, Foster City, CA) Linkage Mapping Set v2.5. Markers D7S2469, D16S3017, D10S1786, D15S1002, D6S1610, and D1S2628 were synthesized by Applied Biosystems with fluorescent dye PET® to allow genotyping in the same lane with the other markers. Samples were PCR amplified in 10μl using 30 ng DNA, 0.5U Taq Gold polymerase (Applied Biosystems), 0.15μM primers, 0.6mM dNTPs (CLP, San Diego, CA), 2.5mM MgCl2 and 1X buffer supplied by the manufacturer. Reactions were amplified in a Veriti thermocycler (Applied Biosystems, Foster City, CA) at 94°C for 12 minutes followed by 40 cycles of 94°C for 30 sec., 55°C for 30 sec., 72°C for 30 sec., with a final extension at 72°C for 10 minutes. PCR products for the individual markers were
