SUPPRESSIVENESS: A NEW FACTOR IN THE GENETIC DETERMINISM OF THE SYNTHESIS OF RESPIRATORY ENZYMES IN YEAST

Abstract

The occurrence is described of 2 different classes of vegetative, respiration-deficient mutants, biochemically identical, but genetically distinguishable by their behavior in crosses with normal yeast. The behavior of these, referred to as "neutral ''petites''" and "suppressive ''petites,''" in such crosses is illustrated by a model experiment. The findings support the hypothesis that: 1, these vegetative mutants result from a loss or inactivation of a particulate cytoplasmic autoreproducing factor required for respiratory enzyme synthesis; and that: 2, the difference between them lies in the destructive or inhibitory effect of the "suppressive" on the above-mentioned normal cytoplasmic particles; this inhibitory effect being not immediate but somewhat delayed.