Figure 7
From: Tunable ultrasensitivity: functional decoupling and biological insights
Four outcomes of cell type specification rendered by a morphogen gradient distributed over a column of six cells.
(A) Graded response, which results in too many “ cell types.” The middle four cells may be abnormal due to partially expressed genes. (B) Threshold response. Only the upper two cells differentiate into a new cell type, because their local morphogen concentrations exceed Ion. (C) Threshold response with lateral inhibition (indicated by the bar-headed arrow). Assuming the lateral inhibition is crosstalk-free. Differentiation of the trailing cell is prohibited due to the raised threshold. (D) Threshold response with lateral inhibition. Assuming severe crosstalk (indicated by the glowing bar-headed arrow). The trailing cell’s gene becomes partially expressed, resulting in an abnormal cell type.
