Searching for sequence directed mutagenesis in eukaryotes.

Sequence directed mutagenesis is a mechanism by which imperfect repeats "repair" each other to become perfect, generating mutations. This process is known to be prevalent in prokaryotes and it has been implicated in several human genetic diseases. Here we test whether sequence directed mutagenesis occurs in the protein coding sequences of eukaryotes using extensive DNA sequence data from humans, mice, Drosophila, nematodes, yeast, and Arabidopsis. Using two tests we find little evidence of sequence directed mutagenesis. We conclude that sequence directed mutagenesis is not prevalent in eukaryotes and that the examples of human diseases, apparently caused by sequence directed mutagenesis, are probably coincidental.