principal component analysis of ychromosome haplotype distribution in 18 ethnic groups in yunnan province based on the historical records 18 of the 26 ethnic groups in yunnan province are the descendant populations of three ancient tribes baiyue baipu and diqiang linguistically belonging to the daic austroasiatic and tibetoburman respectively in order to trace the origins of these native ethnic groups a total of 13 east asian specific ychromosome biallelic markers were used to study the genetic structure of 20 local populations covering all the 18 ethnic groups in yunnan province haplotypes were analysis by pcrrflp method our results showed that h11 and h12 were the predominant haplotypes in the descendant populations of baiyue tribe h5 h6 and h8 were the dominant haplotypes in diqiang descendants and the frequencies of h6 h8 and h11 were very high in the descendant populations of baipu to investigate relationships among 20 populations a three dimensional pc analysis were performed based on the distribution of the 13 haplotypes all populations were divided into two clusters in the pc plot the first cluster was mainly composed by the descendant populations of baiyue and the second one was mainly composed by the descendants of diqiang tribe this result indicated that baiyue and diqiangs paternal lineage had different origins which was in agreement with the historical documents and linguistic classification