Abstract
In a doubly auxotrophic strain of Neurospora, diepoxybutane produces many adenine-reversions and very few inositol-reversions. This does not appear to be due to selective elimination of potential inositol-reversions by inositol-less death. The selectivity of diepoxybutane in this system could be strikingly reduced when treatment was given to a growing culture instead of in vitro to conidia. Possible reasons for this are discussed. Whatever the interpretation of these data, they argue against explaining this case of mutagen specificity solely by the specificity of chemical reactions between mutagen and DNA.
