VH gene family usage. (a) Comparison of VH gene family usage of functional rearrangements found in the combined germinal centers (GCs) and B-cell clusters. VH gene family usage differed significantly from the expected frequencies, assuming each germline gene is equally likely to form a viable rearrangement (P < 0.01). VH1 was significantly under-expressed (P = 0.0066) and VH5 over-expressed (P = 0.046). (b) D gene family use. (c) JH family usage differed significantly from expected (P = 0.0015).