title: Evolutionary analysis of the female-specific avian W chromosome.
abstract: The typically repetitive nature of the sex-limited chromosome means that it is often excluded from or poorly covered in genome assemblies, hindering studies of evolutionary and population genomic processes in non-recombining chromosomes. Here, we present a draft assembly of the non-recombining region of the collared flycatcher W chromosome, containing 46 genes without evidence of female-specific functional differentiation. Survival of genes during W chromosome degeneration has been highly non-random and expression data suggest that this can be attributed to selection for maintaining gene dose and ancestral expression levels of essential genes. Re-sequencing of large population samples revealed dramatically reduced levels of within-species diversity and elevated rates of between-species differentiation (lineage sorting), consistent with low effective population size. Concordance between W chromosome and mitochondrial DNA phylogenetic trees demonstrates evolutionary stable matrilineal inheritance of this nuclear-cytonuclear pair of chromosomes. Our results show both commonalities and differences between W chromosome and Y chromosome evolution.
authors.affiliation: Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden.
authors.forename: Linnéa
authors.initials: L
authors.lastname: Smeds
authors.affiliation: Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden.
authors.forename: Vera
authors.initials: V
authors.lastname: Warmuth
authors.affiliation: Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden.
authors.forename: Paulina
authors.initials: P
authors.lastname: Bolivar
authors.affiliation: Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden.
authors.forename: Severin
authors.identifier: 0000000324396946
authors.initials: S
authors.lastname: Uebbing
authors.affiliation: Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden.
authors.forename: Reto
authors.initials: R
authors.lastname: Burri
authors.affiliation: Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden.
authors.forename: Alexander
authors.initials: A
authors.lastname: Suh
authors.affiliation: Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden.
authors.forename: Alexander
authors.initials: A
authors.lastname: Nater
authors.affiliation: Laboratory of Ornithology, Department of Zoology, Palacky University, 77146 Olomouc, Czech Republic.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Bureš
authors.affiliation: Department of Evolutionary Ecology, Estación Biológica de Doñana-CSIC, 41092 Seville, Spain.
authors.forename: Laszlo Z
authors.initials: LZ
authors.lastname: Garamszegi
authors.affiliation: 1] Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316 Oslo, Norway [2] Natural History Museum, University of Oslo, 0318 Oslo, Norway.
authors.forename: Silje
authors.initials: S
authors.lastname: Hogner
authors.affiliation: Museo Nacional de Ciencias Naturales-CSIC, 28006 Madrid, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Moreno
authors.affiliation: Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Qvarnström
authors.affiliation: Bird Protection and Study Society of Serbia, Radnička 20a, 21000 Novi Sad, Serbia.
authors.forename: Milan
authors.initials: M
authors.lastname: Ružić
authors.affiliation: 1] Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316 Oslo, Norway [2] Norwegian Institute for Nature Research (NINA), 7034 Trondheim, Norway.
authors.forename: Stein-Are
authors.initials: SA
authors.lastname: Sæther
authors.affiliation: Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316 Oslo, Norway.
authors.forename: Glenn-Peter
authors.initials: GP
authors.lastname: Sætre
authors.affiliation: Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, 1117 Budapest, Hungary.
authors.forename: Janos
authors.initials: J
authors.lastname: Török
authors.affiliation: Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden.
authors.forename: Hans
authors.initials: H
authors.lastname: Ellegren
mesh_terms: D000818:Animals; D001717:Birds / Q000235:genetics*; D002645:Chickens / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D019143:Evolution, Molecular; D005260:Female; D046369:Finches / Q000235:genetics; D008116:Lizards / Q000235:genetics; D010802:Phylogeny; D012104:Reptiles / Q000235:genetics*; D012730:Sex Chromosomes / Q000235:genetics*; D020308:Songbirds / Q000235:genetics; D020310:Struthioniformes / Q000235:genetics; D014426:Turtles / Q000235:genetics
chemical_list: D004272:DNA, Mitochondrial