Chromosomal localization of a cytochrome b 5 gene to human chromosome 18 and a cytochrome b 5 pseudogene to the X chromosome

Abstract

We have isolated cDNA clones that code for human cytochrome b 5. Owing to the high degree of evolutionary conservation of cytochrome b 5 sequences and the existence of human and rodent cytochrome b 5 processed pseudogenes, we were unable to map unambiguously the chromosomal localization of the human gene(s) by Southern blot hybridization of DNA from human-rodent somatic cell hybrids. An alternative approach, based on restriction enzyme digestion of PCR-amplified DNA, enabled us to map the human cytochrome b 5 gene(s) to chromosome 18 and one of its processed pseudogenes to the X chromosome. We propose the designations CYB5 and CYB5P1 for the gene and pseudogene loci, respectively.