*2.2.4 Rearrangements to a nonfunctional allele*

Two-thirds of rearrangements produce a nonfunctional allele for at least three main reasons: (i) the reading frame of V and C regions is correctly aligned in only one-third of the cases, (ii) the codons contain three-nucleotide, and (iii) the number of nucleotides inserted or eliminated in the junctions is essentially random.

## *2.2.5 Diversity of receptors in the case of loci with a single V, D, or J segment*

Some loci include only one V, D, or J gene segment. In these cases, all diversity is derived from junctional diversity or subsequent mechanisms of diversity, such as somatic mutation in IG loci, or from gene conversion in IG loci of some species.
