Cloning of chromosome I DNA from Saccharomyces cerevisiae: mutational analysis of the FUN2 transcribed region.

To increase the number of mutationally defined genes on chromosome I from Saccharomyces cerevisiae, most of the FUN2 (Function Unknown Now) transcribed region was deleted by gene replacement. Strains containing the deletion were viable, but grew with a 20% longer generation time. The mutation was recessive. Mutant haploids were able to mate, and homozygous mutant diploids were able to sporulate, giving asci containing four viable ascospores. These results indicate FUN2 is dispensable for the life cycle of S. cerevisiae, but required for an optimal growth rate.