Genetic variations among and within populations of the Oriental fruit fly, Bactrocera dorsalis (Diptera; Tephritidae), detected by PCR-RFLP of the mitochondrial control region

Abstract

A 1.5 kb-long portion of mitochondrial DNA containing the AT-rich control region and its flanking regions was amplified by polymerase chain reaction (PCR) from 217 specimens of Bactrocera dorsalis (Hendel) collected in the Ryukyu Islands of Japan, Thailand, Vietnam, Taiwan, and Hawaii, and obtained from laboratory strains established from populations in regions where the species was formerly distributed. Analysis of restriction fragment length polymorphisms of PCR products (PCR-RFLP) using restriction enzymes DraI and SspI identified 29 different haplotypes. Of these, 27 haplotypes were detected in populations collected in Asian countries in recent years. These populations, including a population collected in the Ryukyu Islands, were similar in terms of haplotypic composition. On the other hand, the Hawaii population and laboratory strains were highly homogeneous, and contained only two and one haplotypes, respectively. Although one haplotype was common among these populations, they did not share any common haplotypes with recently collected Asian populations. Based on the results, we discussed the factors affecting genetic differences among local populations and the utility of the mitochondrial DNA fragment as a genetic marker to define the origin of insects occasionally trapped in the Ryukyu Islands.