Alcohol dehydrogenase activity inDrosophila melanogaster: a quantitative character

Abstract

SUMMARYAlcohol dehydrogenase activity inDrosophila melanogastermay be considered as a quantitative character, since it shows many features typically associated with such traits. Although strains with the electrophoretically fast phenotype generally have activities greater than those with the slow phenotype, presumably reflecting differences in the nucleotide sequences of the structural alleles, within each electrophoretic class there is considerable variation in activity. The expression of the structural gene, in terms of ADH activity, is to some extent regulated by its genetic background. Strains homozygous for particular structural alleles respond to divergent directional selection for ADH activity. Modifiers have been located to theX, second and third chromosomes.