Although the ALDH2*504Lys allele frequency reaches a peak in Southeastern Chinese populations, we cannot draw the conclusion that this allele originated there. The population history shows clearly that Hakka and Minnam Chinese presently in Southeast China are descendants of migrants from Central China (Wen et al., 2004). The indigenous populations in South China, such as Hmong-Mien populations (Hmong and She) from the Yangtze River area, and Daic populations (Kam, Laka, Mulam, and Maonan) from the Pearl River area, exhibit much lower frequency of ALDH2*504Lys. ALDH2*504Lys is almost absent in the aboriginal populations of Hainan and Taiwan, the two largest islands in South China. Therefore, it is unlikely that the Southeast Chinese obtained the ALDH2*504Lys allele from the indigenous populations. Unlike the gradually decreasing frequency to the north and west, the allele frequency drops sharply to the south. The allele exists 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
