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

<p>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 <i>syp-1</i> mutant, which is defective for SC formation and for formation of interhomolog COs; and (B, C and D) the <i>zhp-3</i>, <i>msh-5</i> and <i>cosa-1</i> mutants, respectively, which are proficient for synapsis and DNA repair but are defective in conversion of DSBs to COs. Scale bar, 15 µm.