Evidence for mitochondrial introgression between Anopheles bwambae and Anopheles gambiae

There is evidence for introgression between the malaria vectors Anopheles gambiae and Anopheles arabiensis, which belong to the Anopheles gambiae complex. Here we consider their relationship to another member of the complex, Anopheles bwambae. Species identifications were made using rDNA-PCR and revealed one An. bwambae/gambiae hybrid among 459 wild-caught mosquitoes. A 237-nucleotide region of the mitochondrial ND5 gene was sequenced in sixty-nine individuals. The results suggest that there is an An. bwambae specific group of haplotypes. However, two An. bwambae individuals carried haplotypes typical of An. gambiae and An. arabiensis. This is the first evidence for introgression between An. bwambae and other species of the An. gambiae complex and suggests that introgression may be more widespread, also occurring between other members of the complex.