C. elegans male germ cells: Top, gonad dissected out of worm stained with RAD51 recombinase (green), chromatin mark, H3K9me2 (red) to mark the X chromosome, and DAPI (DNA, blue) . Bottom, individual cells from different germline stages: left, mitosis (tubulin, green; CENPA, red; DAPI, blue); middle, meiotic prophase (pachytene): top, aligned homologous chromosomes (synaptonemal complex, red and green; DAPI, blue); bottom, nuclear pore complex (yellow) and DAPI (blue) and right, the meiosis I division (tubulin, green; membrane protein, red; DAPI, blue).