Gene duplication and gene conversion in the Caenorhabditis elegans genome

A comprehensive analysis of duplication and gene conversion for 7394 Caenor habditis elegans genes (about half the expected total for the genome) is pr esented. Of the genes examined, 40% are involved in duplicated gene pairs. Intrachromosomal or cis gene duplications occur approximately two times mor e often than expected. In general the closer the members of duplicated gene pairs are, the more likely it is that gene orientation is conserved. Gene conversion events are detectable between only 2% of the duplicated pairs. E ven given the excesses of cis duplications, there is an excess of gene conv ersion events between cis duplicated pairs on every chromosome except the X chromosome. The relative rates of cis and trans gene conversion and the ne gative correlation between conversion frequency and DNA sequence divergence for unconverted regions of converted pairs are consistent with previous ex perimental studies in yeast. Three recent, regional duplications, each span ning three genes are described. All three have already undergone substantia l deletions spanning hundreds of base pairs. The relative rates of duplicat ion and deletion may contribute to the compactness of the C. elegans genome .