Experimental evidence of functional innovation in the CENP-O C-terminal RWD domain. Mouse oocytes expressing mouse, rat, or chimeric CENP-O–GFP were fixed in meiosis I and stained for centromeres (CREST) and DNA (DAPI). (A and C) Images show maximum intensity projections; scale bars, 5 μm. (B and D) Graphs show CENP-O–GFP intensity at centromeres; for each construct, n ≥ 722 centromeres from ≥19 cells from three (B) or two (D) independent experiments. Each spot represents one cell; bars: mean intensities with standard deviation; ****P < 0.0001, ns: not significant, one-way ANOVA with Tukey’s multiple comparison test (B) or two-tailed Student's T test (D).