Phylogenetic relationships of Greek Apis mellifera subspecies based on sequencing of mtDNA segments (COI and ND5)

Honey bee Apis mellifera L. populations from various areas of Albania, Bulgaria, Cyprus, Greece, Italy, Slovenia and Turkey, together with a genetically improved commercial strain exported all over the world were studied using sequencing analysis of two mitochondrial regions, the ND5 and the COI gene segments. The aim of this study was to examine the phylogenetic relationships among these honey bee populations, to investigate the existence of gene flow as a result of migratory beekeeping and commercial breeding, and to find out if these subspecies can be discriminated. Seven and eight different haplotypes were revealed for the COI and ND5 gene segments respectively, while the combined data set consisted of twelve different haplotypes. Among the two DNA segments studied, the highest genetic divergence values were observed in COI. In both genes the highest divergence value was among A. m. ligustica colonies and all others. All the phylogenetic trees constructed by Maximum Parsimony, Neighbour-Joining and Bayesian Inference analyses exhibited exactly the same topology for COI and ND5 separately, as well as for the concatenated data set; A. m. ligustica forms the most distinct clade. Our study presents the first comprehensive sequencing analysis of A. mellifera subspecies occurring in Greece and it is the first time that sequencing data from ND5 mtDNA gene segment have been obtained at the population level.