Mutation processes operating in the human genome. Different classes of mutated loci have been plotted on a graph indicating the mutation rate and the number of bases involved in the mutation. Those mutation processes that involve HR are shaded in red. References for different classes of mutated loci are as follows: base substitutions , short indels , microsatellites [20, 21] pathogenic triplet repeats , telomere repeats , rDNA repeats [24, 25], minisatellites , satellites, retroelement insertions , duplicated sequences  and rearrangements in the single copy portion of the genome . Only the higher-order repeat structure of satellites is shown, indicating that this is likely to be the mutable unit.