Microtubules depolymerize in embryos exposed to anoxia. Metaphase blastomeres were examined from embryos exposed to either normoxia (A-D), or anoxia for 30 minutes (E-H), 6 hours (I-L), 12 hours (M-P), 24 hours (Q-T) or 72 hours (U-X). Embryos were stained with DAPI (A, E, I, M, Q, U), and antibodies that recognize microtubule protein YL1/2 (B, F, J, N, R, V), and DM1A (C, G, K, O, S, W). Images were merged (D, H, L, P, T, X). Scale bar equals 2 μM.