A gene encoding Saccharomyces cerevisiae sterol .DELTA.14 reductase of the ergosterol biosynthetic pathway is isolated and cloned by selecting strains carrying sequences on a 2.mu. based vector for resistance to a morpholine fungicide such as fenpropimorph. Four distinct plasmid inserts which produce morpholine resistance are obtained, and one of these is characterized and sequenced. The purified and isolated DNA sequence encoding sterol .DELTA.14 reductase encodes a polypeptide exhibiting homology to the S. cerevisiae sterol C-24(28) reductase enzyme in the ergosterol biosynthetic pathway.