Phenotypic study of Caenorhabditis elegans brc-2 and mrg-1 mutants. (a) Representative images of meiotic cells at the distal part, near the gonad bend. RAD-51 foci are bright and nuclear in wild-type (WT) animals whereas RAD-51 foci appear less intense and weakly diffuse in the cytoplasm, reduced but often dispersed and intense in the nuclei, or absent in brc-2, mrg-1 and rad-51 mutants, respectively. There are more RPA-1 nuclear foci in each of the three mutants than in WT animals. 4,6-Diamidino-2-phenylindole (DAPI) panels are merged with the red channel (for WT and brc-2 mutant) and with the green channel (for rad-51 mutant). *Abnormal chromosomal compaction. (b) Quantitation of RAD-51 and RPA-1 foci per nuclei in several germ cell lines of WT animals and brc-2 and mrg-1 mutant animals. Number of cells scored (n) and standard deviation of the mean indicated. **Significant differences relative to WT (Mann-Whitney U test, P < 0.001). (c) SYTO-12 staining in synchronized adult worms. Left top panel: an animal heterozygous for the brc-2 mutation (according to green fluorescent protein expression at the pharynx) shows WT SYTO-12 staining (that is, one to two labeled cells at the gonad bend). Right top and left bottom panels: an increase in SYTO-12-positive cells in the germline of brc-2 and mrg-1 mutants, respectively. Right bottom panel: magnification of the highlighted area in the left panel.