B-lymphocytes evolve towards monoclonality within 8 weeks. The upper panel shows replicate band patterns for IGH gene rearrangement on agarose gels while the lower panel shows corresponding capillary gel electropherograms of the same amplification products at weeks 1–8. (a–e) Panels a–e correspond to LCL-1–LCL-5. A smear of bands on the agarose gels corresponds to a bell-shaped curve of peak sizes on the capillary gels, while a dominant crisp band in agarose is seen as a major peak in capillary gels. In each of the five samples, a single clone predominates by 8 weeks of culture. In the agarose gel of LCL 4, the consistent duo of bands in weeks 1–4 is interpreted to represent biclonal B cells, as opposed to biallelic IGH rearrangement in a monoclonal line, as evidenced by the single band at week 8; the aberrant pattern at week 8 in the capillary gel does not match the clear monoclonal pattern seen in the corresponding agarose gel of the same product.