Evolutionary analysis of the female-specific avian W chromosome

Nat Commun. 2015 Jun 4;6:7330. doi: 10.1038/ncomms8330.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Birds / genetics*
  • Chickens / genetics
  • DNA, Mitochondrial / genetics*
  • Evolution, Molecular*
  • Female
  • Finches / genetics
  • Lizards / genetics
  • Phylogeny
  • Reptiles / genetics*
  • Sex Chromosomes / genetics*
  • Songbirds / genetics
  • Struthioniformes / genetics
  • Turtles / genetics

Substances

  • DNA, Mitochondrial

Associated data

  • BioProject/PRJEB7359