Cis-acting mutation and duplication: History of molecular evolution in a P450 haplotype responsible for insecticide resistance in Culex quinquefasciatus

► We found a novel haplotype of a cytochrome P450 isoform, Cyp9m10, in southern house mosquito. ► The haplotype was an evolutionary intermediate form of the insecticide resistance factor. ► The duplication of Cyp9m10 was occurred after a cis-acting mutation. ► The cis-acting mutation may have modified the phenotypic consequence of the duplication.