TABLE 3

Comparison of γ-ray-induced chiasma formation in spo-11 and msh-5 mutants

% bivalentsa (no. of nuclei scored)
Genotypeγ-Irradiation16 hrb18 hrb20 hrb
spo-11 0.6 (30)NDND
spo-11 +87.4 (115)98.8 (55)91.1 (56)
msh-5 1.5 (55)NDND
msh-5 +3.0 (211)c4.2 (88)d2.2 (59)c

The msh-5(me23) allele was used in this analysis. ND, not determined.

  • a % bivalents = (no. of observed bivalents)/(no. of potential bivalents), where the number of potential bivalents = 6 × (no. of nuclei scored). In some nuclei, individual univalents may lie too close together to be unambiguously resolved, and in such cases will be scored as bivalents.

  • b Time following irradiation treatment.

  • c Not significantly different from unirradiated 16-hr control (0.1 < P < 0.5).

  • d Borderline significance (0.025 < P < 0.05).