Mammalian alcohol dehydrogenases (ADH) 3 form a com-plex enzyme system based on amino-acid sequence, func-tional properties, and gene expression pattern. At least four mouseAdhgenes are known to encode di erent enzyme classes that share less than 60% amino-acid sequence iden-tity. Two ADH-containing and overlapping C57BL/6 bacterial arti®cial chromosome clones, RP23-393J8 and -463H24, were identi®ed in a library screen, physically mapped, and sequenced.