Azaguanine-resistant mutants induced by several mutagens in a neurospora heterokaryon

This paper reports the development of a new system for the detection of forward mutations in a heterokaryon of Neurospora crassa. This system, designed to detect a wide variety of genetic alterations, is based upon the detection of 8-azaguanine-resistant mutants in an adenine-requiring heterokaryon carrying the aza-3 gene. Induction of mutations in the aza-3 gene was detected after treatment of conidia with ultraviolet light, X-rays, ethyl methanesulfonate (EMS), or the acridine mustard, ICR-170. The pattern of appearance of mutant colonies and various factors in mutant selection are discussed.