Translocation breakpoints in the IGH locus. The horizontal axis represents genomic space on chromosome 14 (chr14). The top panel shows the full IGH locus, the middle panel shows an enlargement of the constant region, and the bottom panel shows the smaller region surrounding the end of the variable diversity joining genes. In each panel, the top track indicates the location of translocation breakpoints (vertical tick marks), with symbols describing the identity of the partner region labeled above. Breakpoints shown on the uppermost panel have been binned for visualization. Annotations of the variable diversity joining segments, constant regions, and enhancer elements (Eµ and 3′RR) are depicted below.