A Case of "Maternal" Inheritance in Neurospora crassa

Abstract

The inheritance of mutant characters of Neurospora has not previously been found to be influenced by the way in which crosses were made. Whether protoperithecia were furnished by one parent or the other, the result, in so far as the types of progeny recovered were concerned, was the same. In the case to be considered here, however, the inheritance of a slow-growth character, which has been designated as poky, appears to be dependent upon its being carried by the protoperithecial parent. If the strain which furnishes the protoperithecia is considered to correspond to the maternal parent on the basis that it also furnishes the greater part of the cytoplasm from which the ascospores are derived, then this case appears analogous to those which have been described in other organisms (reviewed by Sonneborn [1]). In its failure to be transmitted (when it is carried by the fertilizing parent and not by the protoperithecial parent) the poky character resembles in behavior the petite character in yeast, described by Ephrussi [2] and his collaborators. A simple comparison of the two cases probably cannot be made, however, since the yeast ascospores arise from a mixture of the cytoplasms of the two parents, whereas, in obligate heterothallic strains of Neurospora, it appears probable that such mixing does not occur. [3-5]