Using genomic data to study insecticide resistance in the house fly, Musca domestica

The house fly, Musca domestica, is a major pest at livestock facilities throughout the world. Insecticides have been the most common control strategy for flies, but many populations have evolved resistance. The speed by which we are able to identify the mutations responsible for resistance has been a major challenge for the development of high throughput resistance monitoring assays as new insecticides are introduced for control. This is particularly true for mutations that cause trans regulation of a gene, which then results in resistance. In this paper we take advantage of the conserved homology of dipteran chromosomes to assign 3069 genes to chromosomes. Of these, 234 were of toxicological interest (CYPs, esterases/hydrolases, glutathione S-transferases (GSTs) and target sites). The chromosomal location of genes known from linkage analysis studies matched the location predicted by homology mapping in ten out of ten cases, indicating a high reliability of our approach. The CYPs, esterases/hydrolases and GSTs were not randomly distributed throughout the genome. They clustered on chromosomes, but the pattern was different between the CYPs, esterases/hydrolases and GSTs. Examples are provided for how the availability of the house fly genome, combined with an ability to assign genes to chromosomes, will help to accelerate research in house flies.