A Kinetic Method to Determine the Cell Cycle Times of Chick Skin Fibroblast Subpopulations

Abstract. We have inferred, from computer simulations of clonal growth data, mean cell cycle time (T_c) for putative subpopulations of fibroblastic cells having unique replicative potentials. the growth kinetics of chick embryo fibroblast clones can be accounted for if it is assumed that: (1) there is a transient, and rather substantial, decline in mean T_c (from 34 to 12 hr) immediately following the commitment of a 'stem' cell daughter to a limited replicative lifespan; (2) the mean T_c increases progressively (from 12 to 48 hr) as 'committed' cells exhaust their remaining replicative potential; and (3) the daughters of committed cells may occasionally become abruptly post-mitotic.