Figure 2. Reproductively old mice ovulate fewer eggs than reproductively young mice, but the proportion of normal and degenerate eggs does not differ between age groups. (A) The number of eggs ovulated into the oviducts of each mouse was tracked, and the graph shows the average number of eggs ovulated per mouse (N = 11 mice per age group, 22 oviducts). A t-test was performed; asterisks denote P < 0.0001. Data are represented as mean ± SEM. The number of morphologically normal eggs ovulated and retrieved from each oviduct from (B) reproductively young and (C) old individual mice. Representative brightfield microscopy images of morphologically (D) normal and (E) degenerate eggs. Scale bars are 100 μm. (F) The graph shows the proportion of morphologically normal and degenerate eggs ovulated from both age cohorts.