Figure 5.—

RE depends on chromosome III sequences for its function. (A) Effect of RE on the rates of spontaneous recombination between two leu2 heteroalleles, one located in place of HML on chromosome III and the other integrated at the URA3 locus on chromosome V. Spontaneous rates of recombination have been measured in strains bearing RE at its natural locus (XW485, top), deleted for RE (ECY382, middle), or bearing RE near the leu2 allele located on chromosome V (ECY389, bottom). The proportion of the use of leu2-K as a donor among LEU⁺ recombinants is also indicated. (B) RE does not induce spontaneous recombination rate outside of chromosome III even when located near a good donor. The spontaneous recombination rate between two arg4 alleles, located at the ARG4 locus on chromosome VIII and at the URA3 locus on chromosome V, is shown in a strain in which RE has been inserted near ARG4 (ECY272) and in the control without RE (ECY269). The proportion of the usage of arg4-Bg as the donor is shown for strain ECY269.