NBS-1 antagonizes NHEJ and promotes efficient HR. (A, Left) Images of individual DAPI-stained diakinesis oocyte nuclei showing that the chromosome aggregation phenotype of the nbs-1 single mutant is suppressed in nbs-1; cku-80 double mutant, which instead displays a mixture of bivalents and univalents. (A, Right) Quantification of DAPI bodies in diakinesis nuclei. (B, Left) Immunolocalization of HTP-3 and GFP::COSA-1 in late pachytene nuclei in whole-mount preparations. (B, Right) Stacked bar graph showing the percentages of nuclei with the indicated numbers of COSA-1 foci, showing that COSA-1 focus formation is partially restored in the nbs-1; cku-80 double mutant compared with the nbs-1 single mutant.