Figure 4.

Rearrangement events at an H chain locus. Rearrangement occurs on both alleles, leading to a B cell with a V(D)J allele and a (D)J allele. If rearrangement can resume at both alleles, then allele 1 might be replaced and allele 2 might undergo further (D)J rearrangements. If allele 1 becomes nonfunctional during clonal expansion, then allele 2 can become functional by a V to (D)J event. Such V(D)Js should be enriched for downstream JHs.