Extensive X chromosome self-synapsis in dog pachytene spermatocytes. Overview of the dog male meiotic prophase and the progression of synapsis between the XY pair. The left panel shows DAPI staining of the different spermatocyte nuclei, the substages are indicated on the left. To the right of the DAPI images, images of the corresponding nuclei stained for the synaptonemal complex proteins SYCP1 (green) and SYCP3 (red) are shown, followed by the merge. The XY pair in pachytene and diplotene nuclei is encircled. Bar represents 10 μm.