Complementation and Dominance Relationships between Protein Subunits

Abstract

When it was thought that proteins were the primary products of gene translation it was difficult to see how alleles could interact to produce something other than the products of their individual action. Now that it is known that most enzymes are oligomeric in structure, consisting often of a number of normally identical polypeptide chains, it is apparent that the joint action of two alleles may produce hybrid protein. Many examples of hybrid enzyme formation in heterokaryons or heterozygous diploids are known, and such hybridization is thought to be the general explanation for allelic complementation (for review see FINCHAM, 1966). It is the purpose of this paper to show how this sort of allelic interaction can act negatively as well as positively, so as to bring about so-called “negative complementation” of mutant alleles or even dominance of a defective mutant over a functional wild type allele.