Genetic variation in the bee mite Tropilaelaps spp. revealed by sequencing the its region and by RAPD analysis

Abstract

Level of genetic variation of sibling mite species, Tropilaelaps clareae and T. koenigerum in Thailand was investigated by sequencing of PCR-amplified internal transcribed spacer (ITS) region of nuclear ribosomal DNA and RAPD-PCR analysis. No sequence polymorphisms in the amplified ITS region were observed among twenty individuals of T. clareae and among five representatives of T. koenigerum. At an interspecific level, nineteen point mutations constituting of ten transitions and nine transversions were found. Moreover, seven gaps resulted from insertions / deletions were observed. The estimated sequence divergence between T. clareae and T. koenigerum was 3.79%. A 5 bp insertion found in T. clareae could be used to dissociate this species from T. Koenigerum. Nevertheless, restriction analysis of an amplified ITS region with Rsa I can also rapidly detected this interspecific variation. RAPD analysis of one hundred and twenty-five of T. clareae (16 samples) and sixteen individuals of T. koenigerum (2 samples) using primers OPA07, OPA11 and OPA12 indicated high genetic polymorphisms in these two species. A total of 153 genotypes was found from all three RAPD primers (60, 58, and 35 patterns from OPA7, OPA11, and OPA12, respectively). The genetic distance among pairs of T. clareae samples was 0.081-0.2314 while that of T. koenigerum was 0.0289. Using RAPD analysis, the genetic distance between these species was estimated to be 0.8464. No evidences of interspecific hybridization were observed. A UPGMA phylogeny indicated large distance between T. clareae and T. koenigerum and monophyletic status of both taxa. For T. clareae, all investigated samples could be allocated into two different groups, consisting of that contained all T. clareae from A. mellifera host and two samples from A. dorsata (E2D and N1D) and another group consisted of all remaining T. clareae from A. dorsata host.