Appropriate dilutions of each culture were plated onto YPD + AdoMet plates to determine the number of see more viable cells, and onto YPD plates lacking AdoMet to determine the number of AdoMet prototrophic recombinants. All rates were determined by the method of the median . Rates and 95% confidence intervals were calculated as described previously . Spontaneous hetero-allelic recombination Rates of spontaneous hetero-allelic recombination were determined as for ectopic gene conversion except that different substrates were used in diploid cells. All strains contained
the sam2-ΔEcoR V-HOcs allele at the SAM2 locus on one copy of chromosome IV, the sam2-ΔSal I allele on the other, and a LEU2 marker replacing the SAM1 coding sequence at the SAM1 locus on both copies of chromosome XII. The sam2-ΔEcoR V-HOcs allele has a 117 bp fragment of the MAT locus disrupting the EcoR V site, while the sam2-ΔSal I allele has a 4 bp insertion disrupting the Sal I site . Mutation rate Rates of mutation
at the CAN1 locus were examined using a previously published assay [8, 10, 18]. At least ten freshly dissected selleck compound segregants were used to inoculate one-milliliter YPD cultures that were grown to saturation at 30°. Appropriate dilutions were plated onto YPD to determine viability and synthetic medium lacking arginine but containing 60 μg/ml of canavanine to select for mutants. Unequal sister Belnacasan manufacturer chromatid recombination (USCR) Rates of USCR were determined using a previously published assay [8, 10, 67]. At least ten freshly dissected segregants containing the USCE construct at the TRP1 locus on chromosome IV and the his3∆200 allele at the HIS3 locus on chromosome XV, were struck out to single colonies on YPD. After three days of growth at 30°, single colonies were used to inoculate one-milliliter YPD cultures, and grown to saturation at 30°. Appropriate dilutions
were plated onto YPD to assess viability and onto medium lacking histidine to determine the number of histidine prototrophic recombinants. Loss of heterozygosity (LOH) Rates of spontaneous LOH by three different mechanisms were assessed using a previously published assay . Freshly dissected haploid Baf-A1 research buy segregants containing either the hxt13::URA3, CAN1, and HOM3 alleles, or the HXT13, can1-100, and hom3-10 alleles on chromosome V were crossed and the resulting diploids struck out to single colonies on YPD. At least 12 independent colonies were inoculated into one-milliliter YPD liquid cultures and grown to saturation at 30°. Appropriate dilutions were plated onto YPD for viability and synthetic medium lacking arginine, but containing 60 μg/ml of canavanine to select for clones resistant to canavanine. After three days of growth at 30° canavanine-resistant (CanR) colonies were replica plated onto synthetic medium lacking either uracil or threonine to assay for the presence of the hxt13::URA3 (Ura+) and HOM3 (Thr+) alleles, respectively.