The human immunoglobulin variable lambda locus IGLV9 gene is a monomorphicmarker in the urban Brazilian population

The physical map of the human immunoglobulin variable lambda locus (IGLV) l ocated on chromosome 22q11.1-q11.2 shows the existence of 52 functional V-l ambda genes distributed among three V-clusters. The IGLV9S1 gene, located i n the V-B cluster, is a sequence tagged site and is a useful marker for res triction fragment length polymorphism (RFLP) population studies. The V-lamb da genes are associated in the genome with EcoRI fragments detectable in So uthern blots of genomic DNA samples. We have analysed DNA samples of an urb an Brazilian population by Southern-EcoRI-RFLP using an IGLV9 gene segment. Among 75 unrelated individuals analysed, we detected a single 6.0 kb EcoRI fragment containing the IGLV9 gene at 100% frequency. Reverse transcriptio n followed by polymerase chain reaction (RT-PCR) of peripheral blood leukoc yte total RNA from unrelated individuals showed that IGLV9S1 is a functiona l gene contributing to the B lymphocyte repertoire. These data represent ev idence for monomorphism of the IGVL9S1 gene in this urban population. We de monstrate that IGLV9S1 is a functional single copy gene and is an important marker in the IGLV locus. (C) 1999 Elsevier Science B.V. All rights reserv ed.