Evolution of the Genetic Regulatory Networks: The Example of the Cell Cycle Control Network From Gastrulation Modelling to Apocatagenesis

The regulatory genetic networks obtained from the evolution and dedicated to important cell physiologic functions like the control of the progression in the cell cycle are often obtained as random networks with some circuits in the core of the associated interactions graphs fed by an upper multi-rooted directed tree coming from sources which represent the controlling genes or microRNAs, and giving orders to a pending multi-rooted directed tree until leaves which express the ultimate proteins necessary at the control points of the cell growth and maturation. We show on this example that during the complexification of the living organisms (from worms to mammals passing through insects), the cell cycle is controlled by a genetic interactions graph, which has multiplied the roots of its upper tree, as well as the leaves of the pending tree as control points of the progression in the cycle; but this graph kept a core which conserved about the same dynamical properties. Certain genes or microRNAs sources of the graph are involved in mammals in negative retrocontrol loops allowing if necessary a modulation of their inhibitory control from the frontier of the graph. We will use this knowledge about the graph dynamics to study a simple model of the development of the primary digestive tube obtained during the gastrulation process. We conclude by proposing a model for the control of the compensatory proliferation after accidents of ageing leading to a functional and/or anatomic partial or total amputation of an organ, which requires a repair morphogenesis in order to obtain a restitutio in integrum, we will call homeogenesis at the organ level (i. e. respecting the organ homeostasis) or apocatagenesis at the cell level (i. e. compensating exactly the dead cells).