Genetic analysis of Bactrocera zonata (Diptera: Tephritidae) populations from India based on cox1 and nad1 gene sequences

The peach fruit fly, Bactrocera zonata, is among the most serious and polyphagous insect pest of fruit crops in many parts of the world under genus Bactrocera. In the present study, the genetic structure, diversity and demographic history of B. zonata in India were inferred from mitochondrial cytochrome oxidase 1 (cox1) and NADH dehydrogenase 1 (nad1) sequences. The efficiency of DNA barcodes for identification of B. zonata was also tested. Genetic diversity indices [number of haplotypes (H), haplotype diversity (Hd), nucleotide diversity (pi) and average number of nucleotide differences (k)] of B. zonata populations across India maintain high level of genetic diversity without isolation by distance among the geographic regions. Non-significant negative correlation between pairwise Fst and geographic distance suggests a high level of gene flow among studied populations of B. zonata. The possibility of sudden expansion of B. zonata revealed through mismatch distribution analysis as well as negative Tajima's D and Fu's Fs values further supported by star-like network of haplotypes. DNA barcoding analysis suggests that B. zonata specimens can be dearly differentiated from other species with 100% accuracy of identification. Therefore, cytochrome oxidase 1 (cox1) barcode sequences generated in the present study could be a valuable source for the rapid identification and global population genetic study of B. zonata.