A suppressor in Neurospora and its use as evidence for allelism

Abstract

In Drosophila recessive mutations have been observed which suppress the effect of specific mutations at other loci. Thus an individual, homozygous for a suppressor gene in the mutant form and for the mutant gene upon which the suppressor acts, is phenotypically wild type, or nearly so. Suppressors of black,(1) purple,(2,3) sable(4) and vermilion(4, 5) are among those, which have been reported. In the vermilion case there is evidence(5) which shows that the action of the suppressor is to restore v+ substance (kynurenine), the formation of which is prevented when the mutant gene vermilion is present in the homozygous condition.