A new type of interaction between spore colour mutants ofAspergillus niger

Summary A new white-spored mutant of the imperfect fungusA. niger is described. Behind the heterokaryotic heads formed with non-allelic spore colour mutants, it shows as a result of crossfeeding a uniform change of colour of the conidial heads in a band up to 4–5 mm deep. This mutation with pleiotropic effects on colour and crossfeeding occurs relatively frequently inA. niger, although it has not been reported previously.Acknowledgment. Thanks are due to Dr A. J. Clutterbuck (Department of Genetics, University of Glasgow, Glasgow) for helpful comments on this work.