Repeated oocyte bisection produces small oocytes that undergo MI. (A) Schematic of the triple bisection procedure showing the generation of B₀, B₁, B₂, and B₃ oocytes. The same colors are adopted for all figures throughout. (B) Oocyte volumes expressed in pL (left axis) or as a percentage of full size oocytes (right axis). Dashed horizontal lines show the expected sizes of half, quarter, and eighth oocytes. (C) Oocyte radii after bisection. (D) Representative images of oocytes expressing tubulin-GFP and H2B-mCherry, with cartoon depiction underneath. Bar, 50 µm. (E) Percentage of oocytes completing MI; n.s. not significant. Error bars indicate 95% confidence interval. In B, C, and E, numbers of oocytes used are indicated in parentheses. In B and C, groups without common letters indicate significant differences (analysis of variance with Tukey’s correction for multiple comparisons; P < 0.0001).