cDNA sequence and organization of the immunoglobulin light chain gene of the duck, Anas platyrhynchos

A cDNA was cloned which encoded an immunoglobulin (Ig) light (L) chain of the White Pekin duck. The organization of the variable (V) and constant (C) domains was analyzed by genomic Southern blotting. The duck L chain gene has a similar chromosomal organization to that of the chicken, with a single λ-like C region and multiple V_L hybridizing elements. The amino acid sequence of the V_L region of the White Pekin duck L chain showed 88% identity with the Muscovy duck and 87% identity with the chicken, the J_L region showed 92% identity with these species, and the C_L region showed 88% identity with Muscovy duck and 66% with chicken. The constraints imposed by the gene-conversion mechanism of generating antibody diversity might account for the similarities of the avian V region sequences.