CELLULAR-RECOVERY, DNA-REPAIR AND MUTAGENESIS - A TALE OF 2 YEASTS

In studies related to recovery and repair mechanisms following DNA dam age, one problem that has been frequently addressed concerns the effec ts of DNA repair on both spontaneous and induced mutagenesis. Among th e eukaryotic organisms which served as unique and valuable systems for investigating this problem are the two yeasts, Saccharomyces cerevisi ae and Schizosaccharomyces pombe. With the basic genetics well worked out in both, these yeasts have provided the experimental tools for com parative analysis of mechanisms of DNA repair which show a great deal of diversity between the two unicellular eukaryotes. Since the present issue focuses on the contributions of R.H. Haynes to the area of DNA repair and mutagenesis, we have chosen to discuss those specific aspec ts of our studies which are directly or indirectly related to or influ enced by his research in this field. These include (i) liquid holding recovery, (ii) production of two strand mutations and the concept of h eteroduplex repair, and (iii) understanding of pathways of repair thro ugh construction of supersensitive mutants in yeast.