Morphogenetic cycle model: Clarifying several stages of embryo, brain, lung, and heart

Evidence is presented concerning some theories proposed for the spatiotemporal structures underlying the morphogenetic processes of human beings. First, previously reported biological data on the temporal aspects underlying the embryonic and morphologic processes reveal that a fundamental bio-clock with about a six-fold beat cycle controls the time of the emergence of human organs. This refers to the branching time between periodic bifurcation events corresponding to the emergence of organs in the early developmental stage of the nervous system, the respiratory system, and the circulatory system. Second, our experimental data on the cell divisions of yeast show that relatively outer cells on the surface of a cell colony symmetrically divide into child cells, whereas inner ones close to the center of the colony differentiate asymmetrically.