Figure 13.

Analysis, using BASELINe (33, 34), of selection pressure on the diversification of residues of the framework region (FR) and complementarity determining region (CDR) with an origin in six germline genes [IGHV1-18 (A), IGHV2-5 (B), IGHV3-23 (C), IGHV4-39 (D), IGHV5-51 (E), and IGHV6-1 (F)]. There is a profoundly more negative selection of diversification of residues of FR2 and FR3 than of CDR1 and CDR2 but there is no evidence for positive selection in the substitution pattern of CDR of sequences derived from any of the individual germline genes. Indeed, overall there is evidence for negative selection for substitution also in the CDR (G).