The ethnic groups that inhabit the present-day country of Mongolia have a complicated demographic history that has involved several waves of migration of different peoples at different times, especially over the past ten to twenty millennia. The genetic variation in contemporary populations in Mongolia has not been extensively studied. Adding to the interest in genetic studies in Mongolia, previous research has suggested that Mongolia may be a source of the founding population for the New World. However, few results have confirmed this hypothesis. Moreover, the genetic contribution of Mongolians to the gene pools of contemporary populations in Southeast Asia and Oceania has also not been extensively examined. Research on the genetic affinities of Mongolian ethnic groups remains scarce, and the impact of genetic admixture of ethnic groups of exogenous origins is not known. We review the history and demography of Mongolia as well as the genetic studies that relate to understanding variation within the contemporary ethnic groups of Mongolia. Future studies should concentrate on analyzing Y-chromosome variation as to enrich the results from some of the studies performed on mtDNA variation within Mongolia. They should also seek to determine the possible genetic contributions of the ancient Mongolian inhabitants' participation in the settlement of the New World, as well as their genetic contribution to the gene pools of modem populations of Southeast Asia and Oceania. To clarify the complex population history of Mongolia, variation in the mtDNAs of 190 individuals from several Mongolian ethnic groups was analyzed. We used PCR-RFLP analysis to type for coding region SNPs and HVR-I sequencing to assess control region variation in these groups. The resulting data provide insights into the origins and affinities of these populations with East Asian groups, their relationships to neighboring Turkic speaking groups, including indigenous Altaians, and their possible role in the peopling of the Americas
