Figure 2: Apoptosis in male germ cells, and morphology of epididymal spermatozoa in wild large Japanese field mice captured at Fukushima (Site 1) and Aomori (Site 3) in 2013.

(a,b) Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining and hematoxylin counterstaining of seminiferous tubules (Solid arrowheads: Apoptotic cells). (c,d) Phase-contrast micrograph of spermatozoa (Open arrowheads: spermatozoa with abnormal morphologies).