Mutational Analysis of Natural Alleles at the B Incompatibility Factor of SCHIZOPHYLLUM COMMUNE: alpha2 and beta6.

The B incompatibility factor of the fungus Schizophyllum commune having allelic specificity alpha2-beta6 was subjected to mutagenesis by X-irradiation. Five types of mutations were recovered, four of them new types previously unreported. All lead to loss of the B-factor regulatory function; three of the five have retained their allelic specificity. The mutations map in three closely linked sites: Balpha, Bbeta, and between Balpha and Bbeta.