TABLE 2

Genetic evidence that Rad32 and Rad50 are not required for meiotic DNA breakage: rec mutations blocking DNA breakage suppress the low viable spore yield of rad32 and rad50 deletion mutants

Relative viable spore yield (%)b
rad genotypearec+rec6Δrec12Δ
+10015.7 ± 1.3 (8)9.9 ± 0.7 (8)
rad32Δ0.094 ± 0.01 (8) 6.5 ± 1.0 (4)3.8 ± 0.5 (4)
rad50Δ0.062 ± 0.008 (8) 4.4 ± 1.2 (4)4.2 ± 0.8 (4)
rad32Δ rad50Δ0.050 ± 0.002 (4)ND3.8 ± 0.3 (4)
  • a Alleles were rad32::ura4+ (Tavassoli et al. 1995), rad50::kanMX (Hartsuiker et al. 2001), rec6-151::LEU2 (Lin and Smith 1994), and rec12-152::LEU2 (Lin and Smith 1994) and were homozygous mutant or wild type as indicated. Three pairs of parental strains were used for the rad+ rec+ crosses, two for the rad50Δ rec+ crosses, and two for the rad+ rec6Δ crosses. Complete genotypes and genealogies are available upon request.

  • b Mating and meiosis were on SPA agar at 25°. Viable spore yields are expressed relative to wild-type matings done concurrently, which produced 5.8 ± 0.5 (n = 16) viable spores per viable cell (of the less numerous parent) added to the mating mixture. This yield is slightly greater than the theoretical four spores per haploid cell (of one parent) because of slight residual growth of cells on the sporulation medium. Data are the means ± SEM from the number of independent matings indicated in parentheses.

  • ND, not determined.