A cytochrome P-450 gene family mapped to human chromosome 19.

We have recently isolated a cloned cDNA coding for a cytochrome P-450 of human liver microsomal membranes, which corresponds to a major phenobarbital-inducible cytochrome P-450 of rat liver. This human cytochrome P-450 is encoded by a member of a multigene family. DNA extracted from a panel of 12 independent human-rodent somatic cell hybrids was analysed by Southern blot hybridization with the cloned cDNA. The results indicate that all components of this cytochrome P-450 gene family are located on chromosome 19. Evidence from hybrids derived from an individual carrying a balanced translocation suggests a regional localization of 19p13.2----qter. Analysis of human metaphase chromosomes by in situ hybridization localizes this cytochrome P-450 gene family further to the long arm of chromosome 19 in the region q13.1----qter. We propose the designation P450PB for this locus.