High direct estimate of the mutation rate in the mitochondrial genome of Caenorhabditis elegans

Mutations in the mitochondrial genome have been implicated in numerous huma n genetic disorders and offer important data for phylogenetic, forensic. an d population genetic studies. Using a long-term series of Caenorhabditis el egans mutation accumulation lines, we performed a wide-scale screen for mut ations in the mitochondrial genome that revealed a mutation rate that is tw o orders of magnitude higher than previous indirect estimates, a highly bia sed mutational spectrum, multiple mutations affecting coding function, as w elt as mutational hotspots at homopolymeric nucleotide stretches.