Somatic mutation in V_κ genes amplified from IgM⁺⁺IgD⁻ PB B cells by single-cell PCR. (Upper part) V_κ sequences are designated Mo for IgM-only, followed by a sample number and the corresponding V_κ family to which the sequence could be assigned. Shown are the nucleotide differences in the V_κ sequences compared with the corresponding germline genes, which are indicated in the right column. The original references of the respective V_κ germline genes (with the exception of LFVk431³¹) are summarized in a recent review by Schäble and Zachau.27 LFVk431 might represent a polymorphic form of L1.31 Depicted are only those codons of the V_κ germline genes that differed from the respective V_κ sequences. CDRs and codons are numbered according to Kabat et al.32 (Dashes) Nucleotide identity to the corresponding germline genes. (Uppercase letters) Replacement mutations. (Lowercase letters) Silent mutations. (Dots) Codons are absent in the respective V_κ rearrangements. (Lower part) Nucleotide sequences of V_κ-J_κ junctions and number of nucleotide differences to the respective V_κ and J_κ33  germline genes. Indicated are the 3′end of the respective V_κ gene, N region nucleotides (N), and the 5′end of J_κ . (nf ) Nonfunctional rearrangement. The sum of nucleotide differences relative to the corresponding germline genes is shown in the right column. Mutations considered for the analysis are separated by a stretch of at least three identical nucleotides to the 3′V_κ and 5′J_κ ends, respectively. Underlined nucleotides as well as N-region insertions at the V_κ-J_κ junction were not counted as mutations. Sequences are available from EMBO/GenBank/DDBJ under accession no. Z82129-Z82167.