Evidence for mtDNA admixture between the Finns and the Saami

Objectives: The Finns, and to a more extreme extent the Saami, are genetic outliers in Europe. Despite the close geographical contact between these po pulations, no major contribution of Saami mtDNA haplotypes to the Finnish p opulation has been detected. Methods: To examine the extent of maternal gen e flow from the Saami into Finnish populations, we determined the mtDNA var iation in 403 persons living in four provinces in central and northern Finl and. For all of these samples, we assessed the frequencies of mtDNA haplogr oups and examined sequence variation in the hypervariable segment I (HVS-1) . The resulting data were compared with published information for Saami pop ulations. Results: The frequencies of the mtDNA haplogroups differed betwee n the populations of the four provinces, suggesting a distinction between n orthern and central Finland. Analysis of molecular variance suggested that the Saami deviated less from the population of northern Finland than from t hat of central Finland. Five HVS-1 haplotypes, including that harboring the Saami motif and the Asian-specific haplogroup Z, were shared between the F inns and the Saami and allowed comparisons between the populations. Their f requency was highest in the Saami and decreased towards central Finland. Co nclusions: The high frequency of certain mtDNA haplotypes considered to be Saami specific in the Finnish population suggests a genetic admixture, whic h appears to be more pronounced in northern Finland. Furthermore, the prese nce of haplogroup Z in the Finns and the Saami indicates that traces of Asi an mtDNA genotypes have survived in the contemporary populations. Copyright (C) 2001 S. Karger AG, Basel.