9701134 Wills Microsatellite sequences are arrays of short repeated DNA sequences. Their variation in repeat number makes them useful for studying many questions in population biology. Such arrays are highly unstable, and a current topic of debate is over what factors influence the stability of these sequences. This project aims to develop yeast as a model system to study microsatellites, in which hypotheses can be tested by experiments. Development of a yeast model will entail rigorous computer analysis of the complete yeast genome and the determination of mutation rates at a range of loci, using molecular genetic techniques. Over 20 unstable repeats have been identified in yeast. The relative roles of repeat length, repeat sequence, genetic context, and cellular growth conditions on the stability of these repeats will be examined. This project will develop molecular markers for the study of laboratory and natural strains of yeast. The identification of unstable loci in yeast should lead to a powerful model system to test evolutionary hypotheses about mutations at such loci. This work will allow comparative studies of microsatellite sequences as they relate to genome organization, stability, and evolution.
