The Rarity of Evolution Through Gene Shuffling

We examine the role of single copy and duplicate genes in robustness to mutations in the nematode worm Caenorhabditis elegans. We do so by integrating complete genome sequence and micro-array gene expression data with results from a genome-scale study using RNA interference (RNAi) to temporarily eliminate the functions of more than 13,000 worm genes. 88.7% of single copy and 96% of duplicate genes show no detectable phenotypic effect in an RNAi knock-down experiment. We find that mutational robustness is greatest for closely related gene duplicates, large gene families, and similarly expressed genes.