Quantifying the impact of environmental contamination using Drosophila melanogaster across biological sex and genetic background

Abstract

The world is a stressful space. There is a strikingly large knowledge gap in the genetics of stress responses. Stressors are present in nature, such as to exposures to extreme pH, temperatures, and toxicants. We used the response of Drosophila melanogaster to environmental nickel (Ni) as a model to better understand stress, where stress is defined by dysregulation homeostasis. To broadly characterize stress responses, we assayed both males and females of three different types of genetic backgrounds – isogenic, isogenic constructed heterozygotes, and genetically diverse wild-caught lines – of D. melanogaster across a series of phenotypes that range in specificity. We measured Ni response broadly using mortality and more specifically using metabolites. Not surprisingly, Ni negatively impacted every phenotype. Lifespan, feeding, and total lipids were reduced when exposed to Ni. Surprisingly, the Ni effects were substantially different between the sexes, types of genetic backgrounds, and lines. For example, the differences between males and females themselves varied substantially across lines. Similarly, the types of genetic backgrounds and lines differed in response, highlighting genetic complexities. In sum, my results clearly demonstrate that to truly understand the biology of a system, both sexes and multiple lines must be used.