Population Genetics of Latvians in the Context of Admixture between North-Eastern European Ethnic Groups

This article presents a review on population genetics of Latvians, which alongside Lithuanians are the two extant Baltic speaking populations. The article provides a description of genome-wide single nucleotide polymorphism (SNP) data and contains a comparative analysis of the results of studies performed on classical autosomal genetic markers, mitochondrial DNA (mtDNA) and the non-recombining part of the Y chromosome (NRY), with data on neighbouring populations. The study also covers data of recently performed ancient DNA (aDNA) studies carried out on samples from the territory of today's Latvia. The results of population genetic studies have shown a mixture of eastern and western genetic traits in present-day Latvians with only small differences between Latvian subpopulations. Studies of the Baltic "tribal gene" LW^b, as well as the gene's SERPINA1 allele PIZ have indicated the presence of a considerable Baltic admixture in the neighbouring Finno-Ugric and Slavic populations. Although mtDNA analyses have shown that Latvians genetically in general belong to the same common gene pool as most of the Europeans, the Y-chromosomal lineage composition suggests that they are most similar to Northern and Eastern European populations of Lithuanians, Estonians, and Eastern-Slavic populations, which are ethnogenetically closest to them. The analysis of aDNA from the Early and Middle Neolithic did not present any genomic evidence of gene-flow from Central European farmers or any mitochondrial or Y-chromosomal haplogroups that are typical for them in the hunter-gatherers from the territory of today's Latvia and Lithuania.