Genotype-environment interaction for total fitness in Drosophila.
A fundamental assumption of models for the maintenance of genetic variation by environmental heterogeneity is that selection favours different genotypes in different environments. Here, I use a method for measuring total fitness of chromosomal heterozygotes in Drosophila melanogaster to assess genotype-environment interaction for fitness across two ecologically relevant environments, medium with and without added ethanol. Two-third chromosomes are compared, one from a population selected for ethanol tolerance, and the other from a control population. The results show strong crossing of reaction norms for outbred, total fitness, with the chromosome from the ethanol-adapted population increasing fitness on ethanol-supplemented food, but decreasing fitness on regular food, relative to the chromosome from the control population. Although I did not map the fitness effects below the chromosome level, the method could be adapted for quantitative trait locus mapping, to determine whether a substantial proportion of fitness variation is contributed by loci at which different alleles are favoured in different environments.
Fry
James D
JD
Department of Biology, University of Rochester, Rochester NY 14627-0211, USA. jfry@mail.rochester.edu
D000818:Animals; D002875:Chromosomes / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics* / Q000502:physiology*; D004777:Environment; D005838:Genotype; D008954:Models, Biological; D012044:Regression Analysis