Abstract: Dulong, Nu, Lisuo, Achang, Jingpo, Dai and De' ang ethnic groups live along the Nu river valley in Yunnan Province, China. According to historical records, the Nu river valley is an important migrating route of ancient Diqiang tribes. Dulong, Nu, Lisuo, Jingpo and Achang are the descen- dants of Diqiang people; Dai belongs to the ancient Baiyue tribes; De' ang is the descendant of Baipu tribes.
YAP (Y Alu polymorphism), located in Y specific region, is considered to be one of the best markers to study human evolution and migration. The polymorphisms of YAP in these 7 ethnic groups living along the Nu river valley in Yunnan Province were investigated. The results are that the YAP element is present in Nu (1.82 %), Jingpo (12.5 %) and Dai (10 %), but absent in the other 4 ethnic groups. The frequencies of YAP+ are similar in all populations from old Diqiang people except Jingpo along the Nu river valley, coinciding with the reported data of the other descendents of Diqiang. The frequency of YAP+ in Dulong is different from that of Jingpo, which does not support that the Dulong language belongs to Jingpo language branch. The widely different frequencies of YAP+ between Dai and De' ang indicate that they derived from the different ancient tribes.

Key words: YAP; Polymorphism; Ethnic group; Nu river valley