DNA samples

A total of 220 unrelated male samples from four populations, AfAm (n = 17), Cauc (n = 50), Hisp (n = 48), and Kor (n = 105) were used for this study. DNA samples of AfAm, Cauc, and Hisp were obtained from the NHGRI Sample Repository for Human Genetic Research at the Coriell Institute for Medical Research (Camden, NJ, USA; listed Repository ID numbers in Supplementary Table 1) and those of Kor were selected from a previous report.17 All samples were quantified using NanoDrop 1000 spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA) and normalized to 1 ng/µL for subsequent analysis.