Résumé
Anopheles nili is one of the major malaria vectors in Africa with a wide geographic distribution. However, the taxonomic and population genetic studies on this species are scarce. New research tools are urgently needed to genetically characterize this important malaria vector. In this study, a high-resolution cytogenetic map was developed for
An. nili polytene chromosomes. Chromosomes were straightened and subdivided into 46 numbered divisions according to the banding pattern. Population analysis of
An. nili females collected in Burkina Faso revealed the presence of two highly polymorphic inversions on the 2R chromosomal arm. A statistically significant departure from Hardy–Weinberg equilibrium due to a deficit in heterozygotes was detected for inversion 2R
b. To determine chromosome homologies and gene order conservation between
An. nili and other major malaria vectors, PCR probes based on the
An. gambiae coding sequences were mapped to
An. nili chromosomes. Comparative mapping demonstrated that
An. nili chromosomes have an
An. stephensi-like arm association and that whole-arm translocations and paracentric inversions were the major types of rearrangement in evolution of these mosquitoes. The minimum number of fixed inversions among
An. nili,
An. gambiae, and
An. stephensi was calculated using the Multiple Genome Rearrangements (MGR), Genome Rearrangements In Man and Mouse (GRIMM), and Sorting Permutation by Reversals and block-INterchanGes (SPRING) programs. The data suggest that the
An. nili is, at least, as diverged from
An. gambiae as
An. stephensi. We provide evidence that 2L
a/
a arrangement of
An. gambiae is present in outgroup species
An. nili and
An. stephensi confirming the ancestral status of the 2L
a inversion in the
An. gambiae complex. Availability of the new polytene chromosome map, polymorphic inversions, and physically mapped DNA markers for
An. nili will further stimulate population genetic, taxonomic, and genomic studies of this neglected malaria vector.