The complete mitochondrial genome and genetic distinction of the Taiwanese honeybee, Apis cerana (Hymenoptera: Apidae)

The Asian cavity-nesting honeybee, Apis cerana is widely distributed across Asia and nearby islands, showing interesting patterns of genetic differences caused by repeated isolation and re-unification of populations owing to repeated changes in sea levels. In the present study, we analyzed the complete mitochondrial genome of A. cerana from Taiwan and eastern China for the first time. The mitochondrial genomes of these honeybee populations were circular 15,251- and 15,332-bp molecules, respectively, and included 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and one AT-rich control region. The average AT content in mitochondrial genome of Taiwanese and Chinese honeybees was 83.50 and 83.54%, respectively. The heavy strand encoded nine PCGs and 14 tRNA genes and the light strand encoded four PCGs, eight tRNA genes, and two rRNA genes. The ATP6 and ATP8 genes shared 19 nucleotides. Eight PCGs of the A. cerana mitochondrial genome started with ATT, ATP6, COIII, and Cytb genes with ATG, ATP8 gene with ATC, and ND4 gene with ATA. All tRNA genes formed typical cloverleaf secondary structures, except for tRNA-Ser (AGN). The phylogenetic analysis inferred from the 13 mitochondrial PCGs, based on maximum likelihood, indicated that the Taiwanese and eastern Chinese populations of A. cerana are closely related taxa. The 272 sites that differed between A. cerana from Taiwan and eastern China were evenly distributed throughout the mitochondrial genome. We found that the genetic distance between the two population was 0.025, indicating that they are genetically different enough to be considered different subspecies or local populations.