Sex-biased gene expression at homomorphic sex chromosomes in emus and its implication for sex chromosome evolution.

ABSTRACT: Sex chromosomes originate from autosomes. The accumulation of sexually antagonistic mutations on protosex chromosomes selects for a loss of recombination and sets in motion the evolutionary processes generating heteromorphic sex chromosomes. Recombination suppression and differentiation are generally viewed as the default path of sex chromosome evolution, and the occurrence of old, homomorphic sex chromosomes, such as those of ratite birds, has remained a mystery. Here, we analyze the genome and transcriptome of emu (Dromaius novaehollandiae) and confirm that most genes on the sex chromosome are shared between the Z and W. Surprisingly, however, levels of gene expression are generally sex-biased for all sex-linked genes relative to autosomes, including those in the pseudoautosomal region,

SUBMITTER: Vicoso B 

PROVIDER: S-EPMC3631621 | biostudies-literature | 2013 Apr

REPOSITORIES: biostudies-literature