at low frequency in Peninsular Southeast Asia, and is rare in the Southeast Asian islands. If this allele originated in the Southeast Chinese populations after they arrived in the present region, the quick expansion of the allele to the north and west cannot be explained. Therefore, we conclude that the ALDH2*504Lys allele was most probably carried south by the Han Chinese migrants from Central China, rather than originating in the indigenous populations in the region where it now has the highest frequencies.
