Y-Chromosomal Lineages of Latvians in the Context of the Genetic Variation of the Eastern-Baltic Region.

Variations of the nonrecombining Y-chromosomal region were investigated in 159 unrelated Baltic-speaking ethnic Latvians from four different geographic regions, using 28 biallelic markers and 12 short tandem repeats. Eleven different haplogroups (hgs) were detected in a regionally homogeneous Latvian population, among which N1c, R1a, and I1 cover more than 85% of its paternal lineages. When compared its closest geographic neighbors, the composition of the Latvian Y-chromosomal gene pool was found to be very similar to those of Lithuanians and Estonians. Despite the comparable frequency distribution of hg N1c in Latvians and Lithuanians with the Finno-Ugric-speaking populations from the Eastern coast of the Baltic Sea, the observed differences in allelic variances of N1c haplotypes between these two groups are in concordance with the previously stated hypothesis of different dispersal ways of this lineage in the region. More than a third of Latvian paternal lineages belong specifically to a recently defined R1a-M558 hg, indicating an influence from a common source within Eastern Slavic populations on the formation of the present-day Latvian Y-chromosome gene pool.

Mitochondrial DNA origins of the Latvian clefting population.

Latvia has one of the highest prevalence of isolated cleft lip with or without cleft palate (CL/P) in Europe. To clarify the genetic origins of the Latvian cleft population and establish a method for genetic mapping, mitochondrial DNA variation was studied in a population affected with clefting. One-hundred and seven subjects and 351 samples from unrelated healthy volunteers representing four anthropologically, archaeologically and ethno-linguistically different regions of Latvia were selected. The case group showed a higher frequency of haplogroups U4 (p=0.02) and U5 (p=0.0003) than in non-U haplogroups. We hypothesize that U4 and U5 mtDNA haplotype carriers may also carry susceptibility genes for clefts. Future studies will take into consideration these definitions based on mtDNA haplotypes when analyzing genetic variations and their possible contribution to CL/P susceptibility.