Fc Fragment Of IgG, Low Affinity Ib Receptor (FcgR1B)

The high-affinity receptor for immunoglobulin G is encoded by a family of 3 genes that share over 98% of DNA sequence homology. Using both fluorescence in situ hybridization analysis of human cells and Southern analysis of cell lines containing 1b and 1q, Maresco et al. (1996) demonstrated that all 3 genes flank the centromere of chromosome 1 at bands 1p12 and 1q21. FCGR1B was found at 1p12, whereas both FCGR1A and FCGR1C were localized to 1q21. This placed the FCGR1 gene family within a large pericentric linkage group that is conserved between humans and mice. Maresco et al. (1996) hypothesized that the 3 FCGR1 genes were separated by a pericentric inversion, known to have occurred on human chromosome 1, which relocated FCGR1A and FCGR1C to the long arm and left FCGR1B positioned on the short arm.