Fourteen nucleotides in the second complementarity-determining region of a human heavy-chain variable region gene are identical with a sequence in a human D minigene.

A sequence of 14 nucleotides in one human diversity (D) minigene (D2) is identical with a sequence in complementarity-determining region 2 (CDR2) of one human gene for the variable region of the heavy chain of immunoglobulin. The finding that nucleotide segments present in a D minigene can appear in CDR2 raises the possibility that other minigene segments may be involved in the generation of antibody diversity and complementarity or that nucleotide segments may move from one CDR to another by a gene conversion mechanism.