title: Quantitative genetic variance in experimental fly populations evolving with or without environmental heterogeneity.
abstract: Heterogeneous environments are typically expected to maintain more genetic variation in fitness within populations than homogeneous environments. However, the accuracy of this claim depends on the form of heterogeneity as well as the genetic basis of fitness traits and how similar the assay environment is to the environment of past selection. Here, we measure quantitative genetic (QG) variance for three traits important for fitness using replicated experimental populations of Drosophila melanogaster evolving under four selective regimes: constant salt-enriched medium (Salt), constant cadmium-enriched medium (Cad), and two heterogeneous regimes that vary either temporally (Temp) or spatially (Spatial). As theory predicts, we found that Spatial populations tend to harbor more genetic variation than Temp populations or those maintained in a constant environment that is the same as the assay environment. Contrary to expectation, Salt populations tend to have more genetic variation than Cad populations in both assay environments. We discuss the patterns for QG variances across regimes in relation to previously reported data on genome-wide sequence diversity. For some traits, the QG patterns are similar to the diversity patterns of ecological selected SNPs, whereas the QG patterns for some other traits resembled that of neutral SNPs.
authors.affiliation: Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada. yheng.huang@utoronto.ca.
authors.forename: Yuheng
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: John R
authors.initials: JR
authors.lastname: Stinchcombe
authors.affiliation: Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Aneil F
authors.initials: AF
authors.lastname: Agrawal
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001835:Body Weight; D002104:Cadmium / Q000494:pharmacology; D004331:Drosophila melanogaster / Q000187:drug effects / Q000235:genetics*; D004777:Environment; D056084:Genetic Fitness; D014644:Genetic Variation; D049750:Genome, Insect; D020641:Polymorphism, Single Nucleotide; D012641:Selection, Genetic; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D002104:Cadmium; D012965:Sodium Chloride
keywords: Conditional neutrality; Drosophila melanogaster; environmental antagonism; maintenance of genetic variance; spatial and temporal heterogeneity