Genetic relationships between the multiple alcohol dehydrogenases of maize

There are three electrophoretically separable sets of alcohol dehydrogenase isozymes in maize. Previous work has shown that two of these isozymes (Sets I and II) share a subunit in common, since mutations in one of the Adh genes, Adh₁, alter both isozymes. A mutation in the second Adh gene, Adh₂, has now been induced and recovered. This mutant allele also alters two of the three isozymes—Sets III and II. Adh₁ and Adh₂ appear to segregate independently. Gel filtration data show that all ADH isozymes are indistinguishable in size. These findings support the hypothesis that the two Adh genes specify promoters which homo- and heterodimerize, yielding three types of ADH isozymes.This research was supported by National Science Foundation Grant GB 25594. M.F. is a recipient of Public Health Service Genetics Training Grant GM 82-12.