Mitochondrial DNA Evidence For The Origin Of Liqian People From Northwest China

Liqian people,officially recognized as Han Chinese by P.R.China,live in some small village such as Zhelai,Xingshu,Hetan and Jiaojia villedge located in Yongchang County of Gansu province,China.Many of them have light colored hair and Caucasian features,which are sharply different from Han Chinese and most ethnic minorities. Recent years,Liqian people were well known to all with controversial hypothesis of ancient Roman mercenary origin.In 1955,Homer H.Dubs proposed that some Roman soldiers captured by the Parthians after Crassus's defeat at Carrhae in 53 B.C.were eventually hired as mercenaries by a Hun warlord in the western frontier.Finally they were resided in China(Dubs 1955 and 1957).Several years has passed,the origin of the Liqian people mainly focused on the research of history,archeology,linguistics,culture,physical characteristics and customs,which were easily restricted and impacted by the objects of researchers.At the same time,it's very difficult to obtain direct evidence.The nucleotide sequence of human being is stablility genetic from generation to generation,with the development of DNA analysis techniques,in particular,the genetic markers of maternally inherited of mtDNA and the patermal genetic of Y chromosome have been accepted as a Golden Key to interpretated the origin,movement and evolution of population in the world," Therefore,building the haplogroups of Liqian people,using DNA analysis technology from the perspective of population genetics,has become a powerful tool to solve this issue.Due to the study of non-recombinant Y chromosome has been completed(Zhou et al 2007).Therefore,to explore the ethnic origin of Liqian people through the perspective of maternal inheritance of mtDNA is particularly important.In order to explore the origin and demographic history of Liqian people,the mitochromosome DNA haplogroups of 87 Liqian individuals from northwestern China were analyzed.The mtDNA haplogroups of Liqian were restricted by comparing the motif with previous study.The mtDNA haplogroups revealed that 96.6 percentage of mtDNA haplogroups of Liqian people is fell into the common of the Southeastern Asian haplogroups,such as haplogroups A,B,D,F,and M~* in this study.Only approximately 3.4 percentage Liqian people's haplogroups(H,U2e and J1b1) are restricted in western European haplogroups,and these haplogroups are also appeared in central Asian. according to the needs of research,we also collected the mtDNA haplotype frequency of another 24 ethnicities which were from China,Europe and central Asia.Then a Principal Component Analysis(PC) among in these ethnicites have done.The principle component analyses indicated that Liqian people is closer to Chinese Han populations than other ones.In conclusion,the results of maternal genetic variation of Liqian people did not support the hypothesis that they are the descent of ancient Roman's soldiery. Therefore,Liqian people are a mixed population of Chinese Han and center Asian or European,and Chinese ttan has a predominated contribution to them.