CHROMOSOMAL LOCATION OF THE HUMAN-IMMUNOGLOBULIN LAMBDA VARIABLE-8 (IGLV8) GENE FAMILY OUTSIDE THE MAJOR LAMBDA-LOCUS ON CHROMOSOME 22C11.2

Physical mapping of the human immunoglobulin lambda locus (IGL) on chr omosome 22q11 has shown the existence of at least 52 variable region g ene segments. These V lambda genes are associated with Eco RI fragment s detectable in Southern blots of genomic DNA samples. The current phy sical map of the IGL locus includes a unique V lambda 8 gene (IGL8a, a ccession no. Z73650) in a 3.7 kb EcoRI fragment. However, our Southern blot-EcoRI-restriction fragment length polymorphism studies on the Br azilian population using a specific probe for the V lambda 8 gene (pVL 8 probe) have revealed the presence of two additional fragments bearin g V lambda 8 sequences (8.0 kilobase (kb) at 100% frequency and 6.0 kb at 10% frequency). We have used human/rodent somatic cell hybrid DNAs to locate these new V lambda 8 genes outside the major locus on chrom osome 22q11.2. Polymerase chain reactions using specific primers for t he IGLV8a gene on the somatic hybrid panel showed that chromosome 8 (b esides 22q11) also comprises V lambda 8 sequences. This finding repres ents evidence for the dispersion of the human IGLV8 gene family outsid e the major locus (orphan genes). (C) 1997 Elsevier Science B.V.