藉由EdU結合受精卵顯示

授精後20h結束有絲分裂進入S-phase

授精後30h結束S-phase進入第一次有絲分裂

授精後30h結束第一次有絲分裂進入第二次有絲分裂

https://www.cambridge.org/core/journals/zygote/article/cell-cycle-timing-and-centromere-positioning-in-bos-taurus-zygotes-derived-from-in-vitro-fertilization/700F0A5B996B69BF2BC2B5B1A1A5D19C

In 17 and 20 hpi zygotes, S-phase was assigned if at least one of the pronuclei showed EdU incorporation. 

Percentage of zygotes in other cell cycle stages (e.g. G1, G2 and 8-/16-cell embryos) is not shown.