Mutations of theAmating type factor inCoprinus lagopus

Abstract

TenAfactor mutants and an unlinkedAsuppressor mutant were isolated from fruit bodies formed by commonAheterokaryons ofCoprinus lagopus. AllAfactor mutants formed false clamps and lackedAmating-type specificity. FourA5and twoA6mutants had functional α sub-units which were recovered in tests for intra-factor recombination in matings between mutant and wild-type factors. No functional β sub-units were recovered in tests of two of theA5mutants and the twoA6mutants which possessed functional α sub-units. From three other mutants (twoA5and oneA6) neither α nor β sub-units were recovered.The suppressor mutant also formed false clamps but was recessive since stocks carrying it retained theirAandBspecificities when mated with wild-type testers. Fruit bodies formed by monokaryons carrying the suppressor mutant had pale gills bearing varying proportions of abnormal tetrads with less than four spores.