The population studied was the Tujia population, living in the Hunan Province, China. Their ancestors had lived in the region for at least three generations. As a Chinese minority group, the Tujia ethnic group, with a population of 8,028,133 (year of 2000), is mainly distributed in the Wuling mountain area in the three provinces of Hunan, Hubei, and Sichuan. The Tujia population have their own language, which belongs to the Tibetan-Myanmese Language Group of the Chinese-Tibetan Language Family, but the large majority have come to speak the Han and Miao languages, now that the Tujias have been largely assimilated.