Table A1 Frequency of tetrads with at least two detectable recombination events
MSH5 genotypeSPO11 genotypeNo. of NPD (%)No. of TNCO(%)
Wild typeWild type4/462 (0.9)24/462 (5.2)
spo11-HA9/745 (1.2), P = 0.7844/745 (5.9), P = 0.70
spo11-yf16/743 (2.2), P = 0.1144/743 (5.9), P = 0.70
msh5ΔWild type6/766 (0.8), P = 1.0031/766 (4.0), P = 0.39
  • Gfp*+ tetrads were enriched by FACS from one culture for wild type, spo11-HA, and spo11-yf and from two independent cultures for msh5Δ (≥302 tetrads analyzed per culture). Statistical significance was evaluated by a Fisher’s exact test (two-tailed P-value) that compared each strain to wild type. Note that the observed NPDs may underrepresent total NPDs because a small fraction of tetrads that appear to display MI nondisjunction (Figure 5G) could have arisen from a four-strand double crossover instead. Such NPD tetrads are expected to be exceedingly rare, however, because they contain a Gfp*+ spore that is also Rfp+ Cfp+, which is an uncommon configuration (≥14-fold less common than the Rfp Cfpconfiguration; see Table 2A). All such tetrads were thus scored as “MI nondisjunction.”