Using the combined gene approach and multiple analytical methods to improve the phylogeny and classification of Bombus (Hymenoptera, Apidae) in China

Next-generation sequencing of the mitochondrial genome of Bombus longipennis Friese, 1918 (Hymenoptera: Apidae)

Bombus longipennis is the species of Bumblebees (Hymenoptera: Apidae), which are important pollinators for wild plants and greenhouses crops. The complete mitochondrial genome (mitogenome) of B. longipennis was determined by next-generation sequencing. The mitogenome was 18,458 bp in size with 87.2% A + T content, containing 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and an AT-rich control region (D-loop). Gene arrangement was found to be identical to those of other mitogenomes of bumblebees (e.g. Bombus terrestris and Bombus ignitus). All 13 PCGs initiated with typical ATN codons. Among them, 11 PCGs terminated with TAA or TAG; only cox2 and nad4 have incomplete stop codon T. All 22 tRNAs can be folded into typical cloverleaf structure. Phylogenetic analysis based on the concatenated nucleotide sequences of all 13 PCGs indicated that B. longipennis was more closely related to other species of subgenus Bombus, which clustered into a monophyletic group.

The complete mitochondrial genome of Bombus filchnerae (Hymenoptera: Apidae) and phylogenetic analysis

Here, we report the complete mitochondrial genome (mitogenome) of Bombus filchnerae (Hymenoptera: Apidae). The genome size of B. filchnerae was 18,553 bp with 88.7% A + T content, containing 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and an AT-rich control region (D-loop). tRNA rearrangement was observed in this mitochondrial genome when compared to those of other bumblebee species (e.g. Bombus breviceps and Bombus asiaticus). All the 13 PCGs initiated with typical ATN codons. Among them, 11 PCGs terminated with TAA, only nad4 and nad5 with incomplete stop codon TA and T, respectively. All the 22 tRNAs can be folded into typical cloverleaf structure, except for trnS1, whose dihydrouridine (DHU) arm forms a simple loop. The phylogenetic analysis based on the concatenated nucleotide sequences of all 13 PCGs indicated that B. filchnerae showed the closest relationship with Bombus pascuorum, forming a mono clade of the subgenus Thoracobombus, with well-resolved relationships among nine Bombus subgenera.