Overall, the kataegic clusters in the breast cancers are distributed over a similar range of lengths to those detected in the yeast transformants (Figure 3A) but the yeast clusters do typically contain a twofold to fivefold lower density of mutations (a mean inter-mutational distance of 1220 bp within the AID* yeast kataegic stretches compared to 209 bp in PD4107a, 335 bp in PD4103a and 763 bp in PD4199a). This evidence concerns the gene AICDA and breast carcinoma.