Genetic diversity of the mitochondrial ND1 gene in the olive fly, Bactrocera oleae (Rossi, 1790) (Diptera: Tephritidae) from Tunisia

For the Tunisian population of the olive fly, Bactrocera oleae, little data are available. To examine the genetic diversity of this population, we sequenced a segment of the mitochondrial ND1 gene in 15 olive fly samples collected from olive trees in northern Tunisia. In addition, two specimens from Italy and four from California were also sequenced. A total of seven different mitochondrial haplotypes were observed in the samples currently sequenced. The Tunisian population of B. oleae showed a level of polymorphism comparable to that found in various populations worldwide. Although a clear phylogenetic separation between the Mediterranean samples was not possible, the Tunisian haplotypes could be assigned to any of the two Mediterranean groups i.e., the western and eastern Mediterranean. Our phylogenetic analyses and ancestral reconstruction method suggested an Asian origin of B. oleae populations and a Mediterranean origin, respectively. These findings contradict previous studies that suggested an African origin for the fruit fly populations.