A Relevant Method for Estimating Cell Cycle of Developing Cell: The Conspicuous Lengthening of Ts during the Early Neural Development of Cynops Embryo: cell cycle analysis/Ts lengthening/early neural development/amphibian embryo).

A new method for estimating cell cycle was proposed and the cell cycles of the presumptive neural cells of Cynops embryo from the gastrula to neurula stages were estimated. Up to the onset of gastrulation, Tg and Tg became recognizable and Ts lengthened more than 10 times of that in the morula stage. The respective phases of cell cycle, espetially Ts became prominently longer as gastrulation and neurulation proceeded. However, the Ts retained a correlation with Tgc as expressed in the following regression equation, Ts=0.795Tgc-0.090, through the early development of presumptive neural cells.