CDNA SEQUENCE AND ORGANIZATION OF THE IMMUNOGLOBULIN LIGHT-CHAIN GENEOF 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 con stant (C) domains was analyzed by genomic Southern blotting. The duck L chain gene has a similar chromosomal organization to that of the chi cken, with a single lambda-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% identi ty with the chicken, the J(L) region showed 92% identity with these sp ecies, and the C-L region showed 88% identity with Muscovy duck and 66 % with chicken. The constraints imposed by the gene-conversion mechani sm of generating antibody diversity might account for the similarities of the avian V region sequence.