60 1.35 planapo objective

All images of meiotic chromosomes after silver staining and immunodetection of 5-MeC and sequential FISH experiments were acquired using a Zeiss Axio Imager.Z.2 wide-field fluorescence microscope equipped with an AxioCam HRm monochromatic camera. Meiocytes embedded in polyacrylamide and embryo sections were optically sectioned using an Olympus FV1000 confocal microscope system equipped with a ×60/1.35 PlanApo objective. Image stacks were acquired by traversing from the top to the bottom of a nucleus in 0.2 µm steps. Image processing, including the rendering of the Z-stacks from a series of optical sections of the meiocytes, was performed using ImageJ (https://imagej.nih.gov/ij/; last accessed 10/12/2018).

Images of the mitotic metaphase chromosomes after FISH were acquired using a Zeiss Axio Imager.Z.2 wide-field fluorescence microscope equipped with an AxioCam HRm monochromatic camera. The meiocytes that had been embedded in the polyacrylamide gel were optically sectioned using an Olympus FV1000 confocal microscope system equipped with a 60×/1.35 PlanApo objective. All of the image stacks were acquired by scanning from the top to the bottom of a meiocyte in 0.25 μm steps and then processed using MBF ImageJ (Wayne Rasband, National Institutes of Health, Bethesda, MD, United States).