Understanding why the present Central China populations exhibit much lower ALDH2*504Lys than the Southeast China populations is crucial in the study of the history of this allele. Both the decrease in Central China and the increase in Southeast China should be accounted for. In the history of China, many Altaic populations moved from the North China to Central China after wars in the 4th, 12th, and 13th centuries which also resulted in the migration of some Chinese populations from Central China to South China. These Altaic populations later merged with the Central Chinese populations after their kingdoms or dynasties ended. The most famous examples are Sienbers (Xianbei, founders of Former Yan Kingdom, Later Yan Kingdom, Western Qin Kingdom, Southern Liang Kingdom and Southern Yan Kingdom of Sixteen Kingdoms Period, and Northern Dynasties), Huns (founders of Han-Zhao Kingdom and Northern Liang Kingdom of Sixteen Kingdoms Period), Khitans (founders of Liao Dynasty), and Jurchens (founders of Jin Dynasty). Those Altaic migrants may have included very few or no individuals carrying the ALDH2*504Lys allele because present Altaic populations have a low frequency of
