Field_1994_Insect.Mol.Biol_3_143

Biochemical and molecular studies have established that in the peach-potato aphid, Myzus persicae, insecticide resistance is conferred by amplification of genes encoding the insecticide-detoxifying esterases E4 or FE4. Here we report that two insecticide-resistant clones of the closely related tobacco aphid Myzus nicotianae have elevated esterases indistinguishable from E4 and FE4 and amplified esterase DNA sequences, and flanking regions, with identical restriction maps to the M. persicae genes. Furthermore, the DNA sequences of c. 630 bp fragments of the E4 and FE4 genes of M. persicae are different from each other but identical to the fragment from corresponding M. nicotianae clones. The existence of apparently identical insecticide resistance genes in the two species can be best explained by the selection of the amplified genes in M. persicae, transfer to hybrids of M. persicae and M. nicotianae by sexual reproduction and subsequent spread through M. nicotianae populations.