High Direct Estimate of the Mutation Rate in the Mitochondrial Genome of <i>Caenorhabditis elegans</i>

Mutations in the mitochondrial genome have been implicated in numerous human genetic disorders and offer important data for phylogenetic, forensic, and population genetic studies. Using a long-term series of Caenorhabditis elegans mutation accumulation lines, we performed a wide-scale screen for mutations in the mitochondrial genome that revealed a mutation rate that is two orders of magnitude higher than previous indirect estimates, a highly biased mutational spectrum, multiple mutations affecting coding function, as well as mutational hotspots at homopolymeric nucleotide stretches.