Field_1996_Insect.Mol.Biol_5_197

The ability of a peach-potato aphid (Myzus persicae) to resist insecticides can depend on both the presence of amplified esterase genes and on differences in their expression. Here we report a polymerase chain reaction-restriction enzyme (PCR-REN) technique which can detect the presence of amplified esterase genes and distinguish between the two possible types of amplified gene (E4 and FE4) and a homologous fragment from susceptible aphids. The technique is quick and sensitive enough to be used on a fraction of an aphid or an individual embryo. Furthermore, it can be combined with a pre-PCR digestion using a methylation-sensitive enzyme (Hpall) to determine whether or not the esterase genes contain 5-methylcytosine, the presence or absence of which is known to correlate with changes in gene expression.