Chromium sensitive mutants of the yeast Saccharomyces cerevisiae

Summary

Ten mutants of Saccharomyces cerevisiae sensitive to CrO₃ were obtained and genetically analyzed. All of them were recessive. Segregation of the sensitivity after crossing them with a wild type strain indicated that the sensitivity of some mutants was determined by single mutations and that of others was caused by multiple mutations. Among 6 mutations found in mutants having single mutations responsible for the sensitivity, 6 loci were distinguished by complementation. One of them was identified as LYS7, the gene previously known as the structure gene for homocitric dehydrase, in terms of co-segregation and co-reversion of chromium sensitivity and lysine dependency which did not complement an authentic lys7 mutation.