Genetic Diversity of Apis spp. in Thailand Inferred from 28S rRNA Nuclear and Cytochrome b Mitochondrial Gene Sequences

Abstract

Knowledge of the genetic diversity of Apis spp. is important in order to provide a better understanding of breeding strategies that relate to the conservation of wild species and colony survival of farmed species. Here, honeybees of five Apis species were collected from 12 provinces throughout Thailand. After DNA extraction, 28S rRNA nuclear (710 bp) and cytochrome b (cytb) mitochondrial (520 bp) gene fragments were sequenced. Homologous sequences (nucleotide identity of over 95%) were obtained from GeneBank using the BLASTn algorithm, aligned, and analysed by maximum likelihood and Bayesian inference phylogenetics. For 28S rRNA, a low genetic variation was detected within species (haplotype diversity ranging from 0.212 to 0.394), while 19 polymorphic sites were detected between species. Although the relative haplotype diversity was high, a low nucleotide divergence was found (0.7%), with migratory species. For cytb, the sequence divergence ranged from 0.24 to 3.88% within species and 7.35 to 13.07% between species. The divergence of cytb was higher than that of 28S rRNA. A. cerana showed two distinct clades between Southern Thailand and the other regions. Groups of A. cerana (Asian cavity-nesting), A. mellifera (European cavity-nesting), A. dorsata (giant open-nesting), and A. florea and A. andreniformis (dwarf bees) were defined in the 28S rRNA and cytb tree topologies.