Populations of Transcarpathia and Bukovina on the genetic landscape of surrounding regions

Abstract

The territory of present-day Ukraine is subdivided into some regions with specific demographic and politic history. Nevertheless, the corresponding subdivision in genetic structure is not revealed in previous investigations: populations of Ukrainians under study were genetically homogeneous on SNP markers of Y chromosome. In the current investigation we studied the Y-chromosomal genetic structure of Transcarpathia and Bukovina populations. Several factors exist to expect the genetic specificity of these populations. Both ones are placed in the Carpathian foothills, at the south-western border of the Ukrainian area. During the last millennium these territories were the parts of different states and were open for ethnically diverse migrations. It was revealed that the major Y chromosomal haplogroups in Transcarpathia population were R1a1a1*(М198), I2a (Р37.2), R1a1a1g (М458), E1b1b1a1 (M78). The major haplogroups in Bukovina population were I2a (Р37.2), R1a1a1*(М198), R1a1a1g (М458), R1b1b2 (М269), E1b1b1a1 (M78), I1 (М253). The Bukovina population differs from the typical Ukrainian population by higher frequency of I2a (Р37.2) and lower frequency of R1a1a1*(М198). Moreover, this is the only population among ones studied in Ukraine where the most frequent haplogroup is I2a (Р37.2) but not R1a1a1*(М198). Such a deviation can be caused by possible mixing with neighbouring southern groups, and Carpathian mountains were not a border for exchange in this case. Interestingly, the haplogroup N1c (M178) is not revealed in Transcarpathia at all, obviously due to the mountain barrier. It was revealed by principal component analysis that Ukrainians from Transcarpathia and Bukovina despite some specific peculiarities are more similar to other Ukrainian populations than to the surrounding ethnic groups such as Poles, Slovaks, Hungarians, Romanians, Moldavians and Gagauzes. Ukrainians of Transcarpathia and Bukovina form the entire genetic continuum with the whole Ukraine on maps of gene distances, confirming the homogeneity of Ukrainian parental gene pool and it’s differentiation from other groups. After performing the analysis of Y-haplogroup spatial distribution, it is supposed that the northern ridges ofCarpathian mountainsare the East-European barrier decreasing the gene flow. It decreases the spreading of haplogroups N1c (М178) and R1a (М198) southward and movement of E1b (М78), R1b (М269), J (М304) and G (М201) northward.