Thesis (M.Eng.)--Chulalongkorn University, 2001

PCR-RFLP of three mtDNA regions (srRNA gene, lrRNA gene and intergenic COI-COII regions) were used to investigated the distribution of northern and southern honeybees Apis cerana populations. Three, four and eight haplotypes were obtained from DraI digestion of PCR-amplified and eleven composite haplotypes were generated. Tweleve composite haplotypes were generated when sample used for PCR-RFLP analysis was covered four geographic locations; 1) Prachuap Khiri Khan 2) Chumphon 3) Yunnan and 4) Hanoi. A UPGMA phenogram based on genetic distance allocated A. cerana in borderline region in to 2 distinct groups: northern and southern. Their distribution areas had overlapped in Amphur Bang saphan, Bang saphan noi, Tha sae and Pa thiu. And the northern population might be colonized by Vietnam honeybees. Only one colony from Prachuap Khiri Khan had the composite haplotype CED. A CED was extremely different from all samples, although the morphological was similarly. It was suspected to be different species. Further study need to classify their actual taxonomic status. Microsatellite DNA analysis of 4 geographic samples (1. Central, 2. South, 3. Prachuap Khiri Khan and 4. Chumphon) was performed by using A. mellifera microsatellite primers. Three microsatellite loci (A28, A107 and A113) showed polymorphic. PCR products of loci A28 and A107 were very difficult to accurately score because of their stutter bands. The heterozygosities of A. cerana were estimated from microsatellite loci A113 was 0.451- 0.550. The analysis of geographic differentiation indicated no differentiation of four geographics of A. cerana.