title: The genetic architecture of resistance to virus infection in Drosophila.
abstract: Variation in susceptibility to infection has a substantial genetic component in natural populations, and it has been argued that selection by pathogens may result in it having a simpler genetic architecture than many other quantitative traits. This is important as models of host-pathogen co-evolution typically assume resistance is controlled by a small number of genes. Using the Drosophila melanogaster multiparent advanced intercross, we investigated the genetic architecture of resistance to two naturally occurring viruses, the sigma virus and DCV (Drosophila C virus). We found extensive genetic variation in resistance to both viruses. For DCV resistance, this variation is largely caused by two major-effect loci. Sigma virus resistance involves more genes - we mapped five loci, and together these explained less than half the genetic variance. Nonetheless, several of these had a large effect on resistance. Models of co-evolution typically assume strong epistatic interactions between polymorphisms controlling resistance, but we were only able to detect one locus that altered the effect of the main effect loci we had mapped. Most of the loci we mapped were probably at an intermediate frequency in natural populations. Overall, our results are consistent with major-effect genes commonly affecting susceptibility to infectious diseases, with DCV resistance being a near-Mendelian trait.
authors.affiliation: Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK. rcogni@usp.br.|Department of Ecology, University of São Paulo, São Paulo, 05508-900, Brazil. rcogni@usp.br.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Cogni
authors.affiliation: Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK.
authors.forename: Chuan
authors.initials: C
authors.lastname: Cao
authors.affiliation: Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Day
authors.affiliation: Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK.
authors.forename: Calum
authors.initials: C
authors.lastname: Bridson
authors.affiliation: Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK.
authors.forename: Francis M
authors.initials: FM
authors.lastname: Jiggins
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D060467:Disease Resistance / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000821:virology*; D004843:Epistasis, Genetic; D014644:Genetic Variation; D040641:Quantitative Trait Loci; D012209:Rhabdoviridae; D018353:Rhabdoviridae Infections / Q000235:genetics*
keywords: genomics/proteomics; insects; parasitology; quantitative genetics; species interactions