Analysis of AID-induced mutations in Iμ-Cμ intron. The number of mutations per total number of bases sequenced is indicated for each category of splenocytes under the corresponding stimulation conditions. The total number of independent clones sequenced is indicated in Table 1. The maps (not to scale) indicate the relative position of the primers used and the sequences examined on the alleles of the homozygous mutant (Δ/Δ) (A), the wt (+/+) (B), and the heterozygous (Δ/+) (C) splenocytes.