Bulgarians vs the other European populations: a mitochondrial DNA perspective

To define the matrilineal relationships between Bulgarians and other European populations we have evaluated the mitochondrial DNA (mtDNA) variation in a sample of 855 Bulgarian subjects from the mitochondrial DNA (mtDNA) perspective. The molecular survey was performed by sequencing ~750 bp of the control-region, which resulted in 557 different haplotypes, and by a subsequent restriction fragment length polymorphism analysis to confirm haplogroup/subhaplogroup affiliation. The classification was carried out according to the most updated criteria [1], allowing the identification of 45 mitochondrial clades. The observed pattern of mtDNA variation indicates that the Bulgarian mitochondrial pool is geographically homogeneous across the country and that is characterized by an overall extremely high frequency of Western Eurasian lineages. In the Principal Component Analysis (PCA), Bulgarians locate in an intermediate position between Eastern European and Mediterranean populations, which is in agreement with historical events. Thus, while the Mediterranean legacy could be attributed to the Thracians, indigenous people that firstly inhabited the Balkans, the Eastern contribution is likely due to the Proto-Bulgarians originating from the Middle East and to the Slavs migrating from North-East Europe.