A paper on C. elegans that’s very informative:
http://www.nature.com/ng/journal/v44/n3/full/ng.1050.html
Chromosome-scale selective sweeps shape Caenorhabditis elegans genomic diversity
Most notable of their findings is evidence of recent selective sweeps on chromosomes I, IV, V and (sort of) X. These sweeps have the potential to fix pseudogenes that might have been present at the time.
linkstream2 microblog 
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