Genetic basis and repeatability for desiccation resistance in Drosophila melanogaster (Diptera: Drosophilidae)

Dehydration is a stress factor that affects organisms in certain natural habitats, so it is to be expected that populations will develop mechanisms that maximize resistance to desiccation. Insects are an excellent model for studying the effects of dehydration as well as the mechanisms and processes that prevent the effects of water loss since the effect of desiccation is greater owing to the higher area: volume ratio than larger animals. Even though physiological and behavioral mechanisms to cope with desiccation are being understood, the genetic basis underlying the mechanisms related to variation in desiccation resistance and the context-dependent effect remain unresolved. We analyzed the genetic bases of desiccation resistance in Drosophila melanogaster and identified candidate genes that underlie trait variation. Our quantitative genetic analysis of variation in desiccation resistance revealed sexual dimorphism and extensive genetic variation. The phenotype-genotype association analyses (GWAS) identified 71 candidate genes responsible for total phenotypic variation in desiccation resistance. Half of these candidate genes were sex-specific suggesting that the genetic architecture underlying this adaptive trait differs between males and females. Moreover, the public availability of desiccation data analyzed on the same lines but in a different lab allows us to investigate the reliability and repeatability of the results obtained in independent phenotype screens. These analyses indicate a pervasive micro-environment lab-dependent effect since we did not detect overlap between our own estimates of desiccation resistance and the results obtained in another lab.