title: A high-density scan of the Z chromosome in Ficedula flycatchers reveals candidate loci for diversifying selection.
abstract: Theoretical and empirical data suggest that genes located on sex chromosomes may play an important role both for sexually selected traits and for traits involved in the build-up of hybrid incompatibilities. We investigated patterns of genetic variation in 73 genes located on the Z chromosomes of two species of the flycatcher genus Ficedula, the pied flycatcher and the collared flycatcher. Sequence data were evaluated for signs of selection potentially related to genomic differentiation in these young sister species, which hybridize despite reduced fitness of hybrids. Seven loci were significantly more divergent between the two species than expected under neutrality and they also displayed reduced nucleotide diversity, consistent with having been influenced by directional selection. Two of the detected candidate regions contain genes that are associated with plumage coloration in birds. Plumage characteristics play an important role in species recognition in these flycatchers suggesting that the detected genes may have been involved in the evolution of sexual isolation between the species.
authors.affiliation: Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden.
authors.forename: Niclas
authors.initials: N
authors.lastname: Backström
authors.forename: Johan
authors.initials: J
authors.lastname: Lindell
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Palkopoulou
authors.forename: Anna
authors.initials: A
authors.lastname: Qvarnström
authors.forename: Glenn-Peter
authors.initials: GP
authors.lastname: Saetre
authors.forename: Hans
authors.initials: H
authors.lastname: Ellegren
mesh_terms: D000818:Animals; D001483:Base Sequence; D005060:Europe; D019143:Evolution, Molecular; D049810:Genetic Speciation; D008297:Male; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA; D012730:Sex Chromosomes / Q000235:genetics*; D020308:Songbirds / Q000145:classification / Q000235:genetics*