Separation of factors containing R-locus genes in Mormoniella stocks derived from aberrant segregation following incompatible crosses.

Four stocks derived from aberrant segregation of R-locus genes in male progeny following incompatible crosses in Mormoniella have shown characteristics suggesting that genes found on added chromosomal fragments in these stocks have separated from each other. In most cases, this separation was associated with elevated temperatures at the time of and subsequent to fertilization. Data also suggest that the R-locus genes involved are adjacent to a centromere, with the O factor being proximal thereto.