Colonies of Penicillium Notatum and other Moulds as Models for the Study of Population Genetics

Abstract

EXPOSURE of mould colonies to X-rays has long been known to give rise to 'sectorial' mutants. Mutant 'sectors', of course, also arise 'spontaneously' in Fungi as well as in Bacteria. The frequency varies between strains, but is always much smaller than the maximum obtainable by irradiation. Penicillium notatum is no exception, as we have obtained mutant 'sectors' in abundance following irradiation, and occasionally without irradiation. All 'sectors' isolated gave rise to mutant strains, differing from the original in morphological or metabolic properties.