How Can A Transient Signal Switch A Function On Permanently?
René Thomas, Richard D’Ari · 2024
One of the most challenging aspects of cell differentiation is thefact that two cell lines, which, as far as one can tell, are genetically identical, heritably display different phenotypes. At first, one might be tempted to ascribe this to persistent environmental differences. That this usually is not the case is shown by the fact that the phenotypic differences may persist when cell lines are propagated in vitro under identical conditions. It is as though sometime during development a decision had been made and was subsequently maintained through cell generations. Embryologists use the word “determination” to describe this decision, which may take place long before the characteristic aspects of a cell line becomevisible(“differentiation”).