High Coverage Mitogenomes and Y-Chromosomal Typing Reveal Ancient Lineages in the Modern Day Székely Population in Romania

Here we present 115 whole mitogenomes and 92 Y-chromosomal STR and SNP profiles from a Hungarian speaking minority, the Székelys (in Romanian: Secuii, in German: Seklers) living in the Transylvanian part of Romania. We carefully selected the sample providers with local ancestors inhabiting small villages in the area of Székelyudvarhely/Odorheiu Secuiesc. We evaluated the results with population genetic and phylogenetic methods, in the context of those modern and ancient populations that are either geographically or historically related to the Székelys. Our results demonstrate a predominantly local uniparental make-up of the population that also indicates limited admixture with neighbouring populations. Phylogenetic analyses confirmed the presumed eastern origin of certain maternal (A, C, D) and paternal (Q, R1a) lineages and in some particular cases, they can be linked also to ancient DNA data of Hun, Avar and Hungarian Conquest Period populations. The results of our research and the reported data are definitely a qualitative leap, considering that complete mitochondrial DNA data and Y-chromosomal data containing 23 STRs have not been available from the region so far.