TABLE 3

swi5 mutation reduces meiotic recombination and spore viability

Relative ade6+ recombinant
 frequencya
Temperatureswi5+swi5-39
25°10014 ± 3
34° 86 ± 47.7 ± 0.3
Relative viable spore yieldb
Temperatureswi5+swi5-39
25°10039 ± 7
34°107 ± 723 ± 0.5
34°c10092 ± 28
Spore viabilityd
Temperatureswi5+swi5-39
34°0.95 (0.81)0.36 (0.25)
  • a Heterothallic ade6-M26 and ade6-52 strains with the indicated swi5 genotype were mated on EMM2 at the indicated temperature. The ade6+ recombinant frequencies, determined as described in materials and methods, are expressed relative to that for swi5+ matings done concurrently at 25°; this value was 9.3 ± 1.1 Ade+/103 viable spores. Data are means ± SEM (n = 5).

  • b Viable spore yields, determined as in Table 2, are expressed relative to that for swi5+ at 25°, which produced 4.4 ± 0.6 viable spores per viable cell. Data are from the matings described in footnote a.

  • c In these experiments haploid pat1-114 strains were induced for meiosis by the procedure for assaying DNA breakage and repair. Viable spore yields, at 24 hr, are expressed relative to that for swi5+, which produced 0.010 ± 0.0015 (n = 5) viable spores per viable cell induced.

  • d Four-spored asci (10 for swi5+ and 11 for swi5-39) from matings on EMM2 were dissected, and the fraction of spores that produced a visible colony on YEA rich medium recorded. In parentheses is the fraction of 52 random spores, after standard glusulase and EtOH treatment, that produced a visible colony.