Mitochondrial DNA diversity and genetic differentiation of the honeybee (Apis cerana) in Thailand.

Genetic diversity of the honeybee (Apis cerana) in Thailand collected from north, northeast, the central region, peninsular Thailand, and Samui Island (n = 181) was examined by PCR-RFLP of ATPase6-ATPase8. Interestingly, 78 individuals (43.09%) of the southern-latitude bees exhibited length heteroplasmy of the PCR product. The gel-eluted ATPase6-ATPase8 (825 bp) of each bee was restricted with TaqI, SspI, and VspI, respectively. Eight mitotypes were generated and revealed biogeographic differentiation between conspecific samples of A. cerana. AAA, ACA, AAD, BAA, ADA, and ABA were found only in the north-to-central samples (north, northeast, and central region); BBB and BBC were found in the southern-latitude bees; and BBC was restrictively found in the Samui sample. Large genetic distances were observed between each of the north-to-central samples and peninsular Thailand and Samui samples, but lower levels of genetic distance were found within each region. Geographic heterogeneity and phylogenetic analyses indicated that Thai A. cerana could be genetically differentiated into northern Thailand, peninsular Thailand, and Samui Island populations.