Physics and the canalization of morphogenesis: a grand challenge in organismal biology

Abstract

Morphogenesis takes place in a background of organism-to-organism and environmental variation. Therefore, a fundamental question in the study of morphogenesis is how the mechanical processes of tissue movement and deformation are affected by that variability, and in turn, how the mechanics of the system modulates phenotypic variation. We highlight a few key factors, including environmental temperature, embryo size, and environmental chemistry that might perturb the mechanics of morphogenesis in natural populations. Then we discuss several ways in which mechanics – including feedback from mechanical cues – might influence intra-specific variation in morphogenesis. To understand morphogenesis it will be necessary to consider whole-organism, environment, and evolutionary scales because these larger scales present the challenges that developmental mechanisms have evolved to cope with. Studying the variation organisms express and the variation organisms experience will aid in deciphering the causes of birth defects.

HydraRegeneration: Closing the Loop with Mechanical Processes in Morphogenesis

“…Our experiments on Hydra regeneration provide an illustration of this duality; the actomyosin fibers that define the body axis in regenerating Hydra exhibit long‐term structural inheritance (stability) together with the capacity to undergo extensive reorganization (flexibility) . This duality motivates extending the conceptual framework for morphogenesis toward one based on dynamic self‐organization, in which the patterning reflects intrinsic dynamics . These dynamics lead from the onset of morphogenesis (a regenerating tissue or a fertilized egg) to the formation of a viable organism, via a complex interplay of physical (e.g., mechanical stress fields, environmental conditions) and biochemical (e.g., gene regulation, bio‐signaling) processes.…”

“…[7,9]; reviewed in refs. [10,18,32,33,35,[40][41][42][43][44][45]). This includes examples of mechano-sensation and mechano-transduction, in which mechanical signals are sensed and stimulate biochemical signaling.…”

On the role of intrinsic and extrinsic forces in early cardiac S‐looping

“…Natural biological variability is an important issue in development which has not received the attention it deserves (please see von Dassow & Davidson (2011) and references contained therein). The stark natural morphological differences even in embryos at the same stage is an important consideration when studying cardiac looping.…”

The interplay between cell signalling and mechanics in developmental processes

“…Lastly, on the tissue scale the classical processes of secondary induction may serve to signal the success of a particular tissue movement or elicit further morphogenetic movements. The molecular and cellular scale processes that provide feedback from the mechanical processes of morphogenesis are poorly understood and their resolution will provide deeper insights into many larger questions in evolution as well as the nature of disease liability and birth defects 42,95–97 .…”