Genomic evidence for a large-Z effect.

ABSTRACT: The 'large-X effect' suggests that sex chromosomes play a disproportionate role in adaptive evolution. Theoretical work indicates that this effect may be most pronounced in genetic systems with female heterogamety under both good-genes and Fisher's runaway models of sexual selection (males ZZ, females ZW). Here, I use a comparative genomic approach (alignments of several thousands of chicken-zebra finch-human-mouse-opossum orthologues) to show that avian Z-linked genes are highly overrepresented among those bird-mammalian orthologues that show evidence of accelerated rate of functional evolution in birds relative to mammals; the data suggest a twofold excess of such genes on the Z chromosome. A reciprocal analysis of genes accelerated in mammals found no evidence for an excess of X-linkage

SUBMITTER: Ellegren H 

PROVIDER: S-EPMC2674357 | biostudies-literature | 2009 Jan

REPOSITORIES: biostudies-literature