Genetic variation of Apis cerana in Thailand inferred by PCR-RFLP analysis of the mitochoncrial ATPase6-ATPase8 gene

Abstract

Genetic variability and population structure of Thai honeybees Apis cerana was investigated using PCR-RFLP of an amplified 825 bp ATPase6-ATPase8 mtDNA gene. A total of 181 colonies comprising 5 geographic locations (North, North-East, Central, South and Samui Island) were surveyed with three restriction endonucleases (TaqI, SspI and VspI) revealed two, five and six haplotypes, respectively. Ten composite haplotypes were then generated. Only haplotype C of VspI digestion was a population specific genotype for the Samui Island A. cerana. A UPGMA phenogram based on genetic distance among populations clearly allocated 5 geographic samples of A. cerana into 2 distinct group: Northern (North, North-East and Central), Southern (South and Samui Island) with a nucleotide divergence of 1.58%. Furthermore, on the basis of a Monte carlo simulation for geographic heterogeneity, the South and the Samui Island could be separated from each other (P<0.0001). Thirty-nine per cent of investigated samples showed length heteroplasmy. It should be note, however that all heteroplasmic samples were from the South (83%) and the Samui Island (60%). This strong evidences that the Northern and the Southern A. cerana are evolutionary different lineages. Private haplotype from three restriction enzymes digest were found from two colonies in the South. Their composite haplotypes, AEE and AEF, were quite different from all samples of A. cerana. It was suspected to be different species. Further study need to be carried out to clarify their actual taxonomic status.