Assignment of the functional gene for human adrenodoxin to chromosome 11q13----qter and of adrenodoxin pseudogenes to chromosome 20cen----q13.1.

Adrenodoxin is a small iron/sulfur protein serving as an electron-transport intermediate for all mitochondrial forms of cytochrome P450. Southern blots of normal genomic DNA cleaved with six restriction endonucleases probed with full-length human adrenodoxin cDNA revealed complex patterns indicating the presence of multiple adrenodoxin genes. Southern blots of DNA from a panel of mouse/human somatic cell hybrids identified cross-hybridizing adrenodoxin DNA in two loci, chromosome 11q13----qter and chromosome 20cen----q13.1. Examination of adrenodoxin clones from a genomic DNA library in phage lambda revealed some clones bearing gene fragments interrupted by introns and other clones bearing processed pseudogenes. By probing the mouse/human hybrids with unique intronic DNA and by correlating restriction maps of the phage clones with that of uncloned genomic DNA, we show that the authentic transcribed adrenodoxin gene lies on chromosome 11, while pseudogenes lie on chromosome 20.