YEAST ARMS (DNA AT-RISK MOTIFS) CAN REVEAL SOURCES OF GENOME INSTABILITY

The genomes of all organisms contain an abundance of DNA repeats which are at-risk for causing genetic change. We have used the yeast Saccha romyces cerevisiae to investigate various repeat categories in order t o understand their potential for causing genomic instability and the r ole of DNA metabolism factors. Several types of repeats can increase e normously the likelihood of genetic changes such as mutation or recomb ination when present either in wild type or mutants defective in repli cation or repair. Specifically, we have investigated inverted repeats, homonucleotide runs, and short distant repeats and the consequences o f various DNA metabolism mutants. Because the at-risk motifs (ARMs) th at we characterized are sensitive indicators, we have found that they are useful tools to reveal new genetic factors affecting genome stabil ity as well as to distinguish subtle differences between alleles. (C) 1998 Elsevier Science B,V. All rights reserved.