Figure 4.

A-D: Intraclonal variation within cloned PCR products. The sequences are depicted as lines. Only differences with the IgM-derived consensus sequence of FL 8-‘83 are shown. The upper line of each figure represents the sequence that was obtained by directly sequencing two independent PCR products from the same sample. The other lines are the sequences of individual bacterial clones made from the PCR products. Replacement and silent mutations are represented as closed and open circles, respectively. Codon numbers are indicated underneath the symbols. Whereas the consensus sequence of 9aγ contains mutations at positions 50 and 56 as compared to the germ-line gene, the gray symbols at these sites in sequences 1.1, 2.2, and 2.4 represent the germ-line nucleotides. *The mutations at position 110 of clones 2.2 and 2.4 (9aγ) are different from the mutations in the same codon of clone 1.1 and 1.4.