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Processes that break spatial symmetry to produce patterns are at the heart of embryonic
development. The remarkable consistency in the emergent features across a species in spite of the noise that is inherent to the underlying processes serves as a testimony to the robustness of the mechanisms underlying developmental pattern formation.
We propose a framework whereby one can understand how the process of selective gene expression in each cell, that characterizes different phases of development, is regulated by its environment, viz., the cellular ecology it is part of. In particular, we focus on the role of contact-mediated intercellular signaling (similar to ferromagnetic or anti-ferromagnetic exchange interaction in spin models of statistical physics) in allowing information from the cellular neighborhood to influence the adaptive emergence of morphogen signal thresholds that dictate cell fates. This results in local modulations of the positional cues provided by the global field (set up by the
morphogen, similar to a magnetic field in spin systems), allowing interaction-mediated self-organized pattern formation to complement
boundary-organized mechanisms in the context of development. This results in robust developmental outcomes, thereby substantially reducing the uncertainty in the fate adopted by a cell.
The developmental ecology framework we propose also allows us to explain growth arrest (triggered by cessation of the cell cycle "clock") of cells in a tissue as a collective dynamical transition. Our work thus connects abnormalities during development with the onset of diseases such as cancer marked by unregulated cell division. |