Hydra morphogenesis as phase-transition dynamics

TL;DR

This paper models Hydra morphogenesis as a phase transition driven by calcium fluctuations, combining experiments with a field-theoretic model to explain shape changes during regeneration.

Contribution

It introduces a physics-based framework linking calcium dynamics to morphological transitions, validated by experimental controls and predictions.

Findings

Ca2+ fluctuations drive shape transition

Morphogenesis modeled as a first-order phase transition

Experimental validation of model predictions

Abstract

We utilize whole-body Hydra regeneration from a small tissue segment to develop a physics framework for animal morphogenesis. Introducing experimental controls over this process, an external electric field and a drug that blocks gap junctions, allows us to characterize the essential step in the morphological transition - from a spherical shape to an elongated spheroid. We find that spatial fluctuations of the Ca2+ distribution in the Hydra's tissue drive this transition and construct a field-theoretic model that explains the morphological transition as a first-order-like phase transition resulting from the coupling of the Ca2+ field and the tissue's local curvature. Various predictions of this model are verified experimentally.