Files in this Data Supplement:

• Supplementary Figure 1 (Word Document, 141 KB) - Modelling of the proliferation and death of SCID B cells.
• Supplementary Figure 2 (Word Document, 94 KB) - Sequences of switch recombination junctions cloned by PCR from DNA of cultured SW_HELRAG1^-/- and SW_HELSCID B cells.