The organization of the human immunoglobulin λ gene locus

To elucidate the complex structure of the human immunoglobulin λ gene locus, a 1020-kb contig was constructed using 184 cosmid clones and one bacterial artificial chromosome (BAC) clone. A high-resolution physical map of this contig revealed that the entire λ gene locus is 911 kb in length. It contains seven constant region (C(λ)) gene segments and 69 unique EcoRI-HindIII segments that hybridize to variable region gene (V(λ) probes. The VpreB gene, BCRL4, and γ-glutamyl transpeptidase gene (GGT)-like sequences are also located within the λ gene locus. Hybridization analysis suggested that the λ gene locus has undergone extensive amplification events in evolution.