The cell cycle of Xenopus laevis cells in monolayer culture

Analysis of the cell cycle of recently isolated Xenopus laevis cells in culture gave mean values for the duration of G1, S and G2 of 18.0, 8.2 and 5.3 h respectively. After 70 weekly subcultures, cells with 38 chromosomes had equivalent values of 4.7, 6.3 and 3.0 h, and for tetraploid cells of 7.0, 8.9 and 5.0 h. The duration of mitosis was 1.0 h.