Further Evidence of Aberrant Recombination in Neurospora

Wild progeny from intercrosses of pyridoxine mutants have been found in tetrads showing irregular segregation of one or the other of the mutants. [1] These wild types therefore appear not to be true recombinants arising from crossing over between the mutant genes. Earlier, individuals of the genotypes expected to result from two- or three-strand double crossovers involving the regions adjacent to the locus of a pyridoxine mutant had been obtained with surprisingly high frequency from marked crosses between this mutant and its wild allele. [2] Since the frequency was very nearly that with which wild offspring were obtained from intercrosses, the possibility was considered that the apparent double-crossover recombinants might be due not to ordinary crossing over but to the mechanism which operates in the intercross. That these apparent recombinants also are found to accompany abnormal segregation is shown by the experiments reported here