DSB-2 and SUN-1 S8P persist when CO formation is impaired.

Immunofluorescence images of gonads of indicated genotypes from the distal pre-meiotic region to end of pachytene, stained with DAPI and antibodies that recognize DSB-2 and SUN-1 S8P. The zone of DSB-2 and SUN-1 S8P-positive nuclei is extended in: (A) the syp-1 mutant, which is defective for SC formation and for formation of interhomolog COs; and (B, C and D) the zhp-3, msh-5 and cosa-1 mutants, respectively, which are proficient for synapsis and DNA repair but are defective in conversion of DSBs to COs. Scale bar, 15 µm.