title: The X chromosome is a hot spot for sexually antagonistic fitness variation.
abstract: Sexually antagonistic alleles are selected discordantly between the sexes. Experimental evidence indicates that sexually antagonistic fitness variation is abundant in the genome of Drosophila melanogaster. Theory predicts that the X chromosome will be enriched with this type of variation. To test this prediction in D. melanogaster, we sampled, and cytogenetically cloned, 20 X chromosomes and compared their fitness variation to genome-wide levels. At the juvenile stage, in which gender roles are most similar, the X chromosome made no detectable contribution to genome-wide fitness variation. At the adult stage, in which gender roles diverge, the X chromosome was estimated to harbour 45% of the genome-wide fitness variation and 97% of the genome-wide sexually antagonistic variation. This genomic structure has important implications for the process of sexual selection because X-linked sexually antagonistic variation contributes to negative intersexual heritability for fitness, i.e. high-fitness males (females) produce, on average, low-fitness daughters (sons).
authors.affiliation: Department of Ecology, Evolution and Marine Biology, University of California at Santa Barbara, Santa Barbara, CA 93106-9610, USA.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Gibson
authors.forename: Adam K
authors.initials: AK
authors.lastname: Chippindale
authors.forename: William R
authors.initials: WR
authors.lastname: Rice
mesh_terms: D000483:Alleles; D000818:Animals; D005075:Biological Evolution; D004331:Drosophila melanogaster / Q000235:genetics*; D008040:Genetic Linkage / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics*; D005838:Genotype; D011110:Polymorphism, Genetic / Q000235:genetics; D012098:Reproduction / Q000235:genetics; D012641:Selection, Genetic; D012727:Sex Characteristics; D014960:X Chromosome / Q000235:genetics*