Interference and NonInterference Recombination Pathways in Yeast

University Of Oregon Eugene, Eugene OR

Investigators

Abstract

Evidence supports the following view of meiotic recombination in yeast: Double-strand-break repair is governed by two pathways, which are distinguished by the products of resolution of their repair intermediates. One pathway (Type I) yields the crossover and noncrossover resolution types expected from the cutting of both Holliday junctions of the intermediate. The other pathway (Type II) yields only one of the two types of crossover resolution that could arise from cutting DNA strands in the intermediate, along with a single noncrossover type that appears to arise without strand cutting. Crossover resolution of Type II intermediates depends on a set of proteins demonstrably required for crossover interference. Crossover resolution of Type I intermediates occurs independently of these proteins, and Type I crossovers display little or no interference. These studies of interference in yeast, which are expected to yield findings applicable to mammals and green plants as well, promise to provide an explanation for documented differences in crossing-over in yeast as compared with Drosophila. In so doing, they will enhance our understanding of meiosis, an essential feature of sexual reproduction. Understanding this basic biological process will enable biologists to develop better solutions to many of society's most pressing problems