Genetic differentiation among Thai honeybees Apis cerana using microsatellite variation and nuclear ribosomal RNA genes

Abstract

Level of genetic differentiation and populating structure of Thai honeybees A. cerana from five different geographic locations (North, Central, North-East, Southand Samui Island) was investigated using sequencing of PCR-amplified internal transcribed spacer (ITS) region of nuclear ribosomal DNA and variation of microsatellite DNA. The GC content of amplified ITS region in A. cerana was 52.1%. Low sequence polymorphisms in the amplified ITS region were observed among 21 investigated sequences covering five geographic samples. Only 4 point mutations were found constituting of 1 transversion and 3 transition. Using the information on the point mutation, the origin of A. cerana from the Northern group (North, Central andNorth-East), Southern and Samui Island could be unambiguously traced. Microsatellite DNA analysis in 5 geographic samples included 265 colonies by 13 A. mellifera microsatellite loci using Polymerase Chain Reaction (PCR). Three microsatellite loci (A28, A107 and A113) were shown to be polymorphic with number of alleles at each locus of 24, 10 and 3 alleles, respectively. The average heterozygosities of Thai A. cerana estimated from these microsatellite loci was 0.18-0.46.The analysis of geographic heterogeneity and phylogenetic reconstruction using the Neighbor-joining approach divided 5 geographic A. cerana samples to 3 different groups consisting of 1)Northern (North, Central and North-East), 2) South and3) Samui Island.