Abstract
A variety of genetic studies has led to the elaboration of several molecular models of recombination. The paradigms for these models are the single-strand nick model and the double-strand break (DSB) repair model. Recently, attention has been paid to a third type of recombination, termed as “single-strand annealing” by Lin. This kind of recombination differs from other mechanisms in that it is inherently nonreciprocal, such that DNA located between homologous sequences will inevitably be lost. A full understanding of the molecular events that actually occur in a particular type of recombination demands the ability to define each of the steps in recombination and to identify the proteins that are essential for catalyzing these events. This chapter discusses a number of different ways in which discrete steps in recombination and the identity of gene products that are important for those steps can be analyzed in Saccharomyces cerevisiae. It discusses the important results that have been obtained using these approaches to study mitotic and meiotic recombination.