Recombination in Saccharomyces cerevisiae: REC-gene Mutants and DNA-binding Proteins

Abstract

In previous studies we have compared the properties of mitotic and meiotic recombination that involve gene conversion, intragenic recombination, and intergenic recombination (Esposito 1978, 1984; Malone et al. 1980; Bruschi and Esposito 1983). These investigations demonstrated that mitotic and meiotic recombination differ in the time of onset of recombination relative to chromosomal replication, the frequency of symmetric Holliday structures, and the coincident conversion of genetic markers at widely separated loci located on the same chromosome. Thus, in mitotic cells recombination is frequently initiated prereplicationally in contrast to analogous meiotic recombinational events, which are initiated postreplicationally. Mitotic coincident heteroallelic recombination at widely separated loci and en bloc nonreciprocal segregation of heterozygous markers on the same chromosome provide evidence for mitotic conversional events that involve extensive chromosomal regions. In this study we have employed recombinant DNA techniques to document the formation of lengthy DNA recombinational intermediates resulting in conversion of heterozygous plasmid...