The developmental basis for canalization

20 June 2014

Benedikt Hallgrímsson
Department of Cell Biology and Anatomy
Alberta Children's Hospital Institute for Child and Maternal Health
University of Calgary


Canalization refers to the suppression of either genetic or environmental variance. The evolution of mechanisms that regulate the expression of variance is a fundamental feature of complex developmental systems. The genetic and developmental basis for this phenomenon, however, is largely unknown. There are two basic views on this issue. In one, there are specific evolved mechanisms such as heat shock proteins that suppress or regulate the expression of variance in response to environmental or genetic perturbations. In the other, canalization occurs as an emergent property of developmental systems. I argue that both theory and evidence supports the latter view. Canalization effects can emerge from nonlinearities in development, changes to patterns of network redundancy and from dysregulation of morphogenetic processes. I will discuss examples that support this view both from our work and that of others. Through these examples, I hope to critically evaluate the utility of the concept in light of our increasingly complex-systems informed understanding of development.

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