| The oriental fruit fly (Bactrocera dorsalis) species complex contains at least 75 described species, some of which are major agricultural pests. Many of them cannot be easily or accurately identified using traditional taxonomic characters. Molecular approaches based on DNA analysis may improve and augment existing tools for identification purposes. For this purpose, DNA sequences from several nuclear and mitochondrial loci were detected in the form of polymorphisms and designated as alleles and/or haplotypes from species within this complex. These DNA markers have also been analyzed in several ways.;Nuclear genes were analyzed using an EPIC-PCR strategy. Here, primers are designed to anneal to the conserved coding regions so that PCR amplification is directed across the more variable intron region. Implementing this approach, I amplified actin genes from several specimens. PCR products were cloned, sequenced and aligned for analysis. Allelic variants were identified and oligonucleotides corresponding to them were synthesized. In a DNA array format, we were able to rapidly and accurately identify the species and genotype of individual specimens. Gene sequences from additional nuclear loci (beta-tubulin 1, beta-tubulin 3 and ITS1) were also evaluated for incorporation into the DNA arrays.;Employing primers designed from the mitochondrial 16S, COI and COII + tRNALys + tRNAAsp genes, amplification products were sequenced and aligned. By directly comparing the mitochondrial DNA sequences, haplotypes were identified for each gene. Using this approach, the genetic variation and relationships of known specimens were evaluated at the population and species level.;These nuclear and mitochondrial data provide a foundation to create a molecular taxonomic reference database spanning various loci, species and populations. These same sequences may be useful to analyze and resolve the systematic relationships of species, and the approaches employed here can also be adapted to study other species complexes. |
