Sodium channel genes and their differential genotypes at the L-to-F kdr locus in the mosquito Culex quinquefasciatus

► This is the first report of multiple copies of the sodium channel gene in the mosquito Culex quinquefasciatus. ► Two genotypes of the mosquito sodium channel gene were detected. ► A strong correlation between the frequency of allelic variation at the L-to-F site at genomic DNA level and the prevalence of L-to-F allelic expression at the RNA level was identified in one genotype. ► This study highlights the complexity of sodium channel genes in mosquitoes.