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Mechanisms for dominance: Adh Heterodimer formation in heterozygotes between ENU or X‐ray induced null alleles and normal alleles in Drosophila melanogaster
Author(s) -
Jiang James C.,
Lee William R.,
Chang S. H.,
Silverman Harold
Publication year - 1992
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.2850200404
Subject(s) - allele , mutant , heterozygote advantage , genetics , biology , dominance (genetics) , drosophila melanogaster , locus (genetics) , amino acid , alcohol dehydrogenase , phenotype , null allele , enzyme , gene , microbiology and biotechnology , biochemistry
Mechanisms for Dominance: Adh Heterodimer Formation in Heterozygotes Between ENU or X‐ray Induced Null Alleles and Normal Alleles in Drosophila melanogaster To study mechanisms for dominance of phenotype, eight ENU‐ and four X‐ray‐induced mutations at the alcohol dehydrogenase ( Adh ) locus were analyzed for partial dominance in their interaction with normal alleles. All ENU and one of the X‐ray mutations were single base substitutions; the other three X‐ray mutations were 9–21 base deletions. All but one of the 12 mutant alleles were selected for this study because they produced detectable mutant polypeptides, but seven of the 11 producing a peptide could not form dimers with the normal peptide and the enzyme activity of heterozygotes was about half that of normal homozygotes. Four mutations formed dimers with a decreased catalytic efficiency and two of these were near the limit of detectability; these two also inhibited the formation of normal homodimers. The mutant alleles therefore show multiple mechanisms leading to partial enzyme expression in heterozygotes and a wide range of dominance ranging from almost complete recessive to nearly dominant. All amino acid changes in mutant peptides that form dimers are located between amino acids 182 and 194, so this region is not critical for dimerization. It may, however, be an important surface domain for catalyzation. © 1992 Wiley‐Liss, Inc.