DURATION OF MITOSIS AND SEPARATE MITOTIC PHASES COMPARED TO NUCLEAR DNA CONTENT IN ERYTHROBLASTS OF FOUR VERTEBRATES

The passage of a wave of tritiated. thymidine-labelled cells through each of the phases of mitosis is analysed in erythroblasts of four vertebrates species, selected because of their widely differing diploid DNA content. Mitotic time (t_m) and relative durations of separate mitotic phases as well as that of the G₂ period are thus accurately determined. Mean duration of t_m appears to vary according to the species specific DNA amount. This relation is approximately the same as for S, for G₁ and for the generation time, which have been previously determined.