title: Variation in Drosophila melanogaster central metabolic genes appears driven by natural selection both within and between populations.
abstract: In this report, we examine the hypothesis that the drivers of latitudinal selection observed in the eastern US Drosophila melanogaster populations are reiterated within seasons in a temperate orchard population in Pennsylvania, USA. Specifically, we ask whether alleles that are apparently favoured in northern populations are also favoured early in the spring, and decrease in frequency from the spring to autumn with the population expansion. We use SNP data collected for 46 metabolic genes and 128 SNPs representing the central metabolic pathway and examine for the aggregate SNP allele frequencies whether the association of allele change with latitude and that with increasing days of spring-autumn season are reversed. Testing by random permutation, we observe a highly significant negative correlation between these associations that is consistent with this expectation. This correlation is stronger when we confine our analysis to only those alleles that show significant latitudinal changes. This pattern is not caused by association with chromosomal inversions. When data are resampled using SNPs for amino acid change the relationship is not significant but is supported when SNPs associated with cis-expression are only considered. Our results suggest that climate factors driving latitudinal molecular variation in a metabolic pathway are related to those operating on a seasonal level within populations.
authors.affiliation: Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794, USA.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Cogni
authors.affiliation: Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794, USA.
authors.forename: Kate
authors.initials: K
authors.lastname: Kuczynski
authors.affiliation: Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794, USA.
authors.forename: Erik
authors.initials: E
authors.lastname: Lavington
authors.affiliation: Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794, USA.
authors.forename: Spencer
authors.initials: S
authors.lastname: Koury
authors.affiliation: Department of Biology, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Emily L
authors.initials: EL
authors.lastname: Behrman
authors.affiliation: Department of Biology, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Katherine R
authors.initials: KR
authors.lastname: O'Brien
authors.affiliation: Department of Biology, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Schmidt
authors.affiliation: Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794, USA walter.eanes@stonybrook.edu.
authors.forename: Walter F
authors.initials: WF
authors.lastname: Eanes
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D000483:Alleles; D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D012621:Seasons; D012641:Selection, Genetic
chemical_list: D029721:Drosophila Proteins
keywords: clines; metabolic genes; natural selection; seasonal selection