Complex interactions of the Eastern and Western Slavic populations with other European groups as revealed by mitochondrial DNA analysis.

Mitochondrial DNA sequence variation was examined by the control region sequencing (HVS I and HVS II) and RFLP analysis of haplogroup-diagnostic coding region sites in 570 individuals from four regional populations of Poles and two Russian groups from northwestern part of the country. Additionally, sequences of complete mitochondrial genomes representing K1a1b1a subclade in Polish and Polish Roma populations have been determined. Haplogroup frequency patterns revealed in Poles and Russians are similar to those characteristic of other Europeans. However, there are several features of Slavic mtDNA pools seen on the level of regional populations which are helpful in the understanding of complex interactions of the Eastern and Western Slavic populations with other European groups. One of the most important is the presence of subhaplogroups U5b1b1, D5, Z1 and U8a with simultaneous scarcity of haplogroup K in populations of northwestern Russia suggesting the participation of Finno-Ugrian tribes in the formation of mtDNA pools of Russians from this region. The results of genetic structure analyses suggest that Russians from Velikii Novgorod area (northwestern Russia) and Poles from Suwalszczyzna (northeastern Poland) differ from all remaining Polish and Russian samples. Simultaneously, northwestern Russians and northeastern Poles bear some similarities to Baltic (Latvians) and Finno-Ugrian groups (Estonians) of northeastern Europe, especially on the level of U5 haplogroup frequencies. The occurrence of K1a1b1a subcluster in Poles and Polish Roma is one of the first direct proofs of the presence of Ashkenazi-specific mtDNA lineages in non-Jewish European populations.