The mitotic delay in response to unreplicated sister chromatids is dependent on the spindle checkpoint. Embryos that were wild type or mad2 mutant and expressing Histone-GFP were injected with Geminin protein. Mitotic duration was recorded during cycle 14 and cycle 15 in which mitoses occurred with unreplicated sister chromatids. Mitosis 15 duration was measured in multiple mitotic domains and identical results were found. Average mitotic duration is shown for cycle 14 (n = 6 embryos) and cycle 15 (n = 12 embryos). Error bars represent SD.