I-SIS Lecture

How Development Directs Evolution

Epigenetics and Generative Dynamics

Invited lecture for Evolution and the Future conference, Hotel Continental-Beograd, Belgrade, Serbia, 14-18 October 2009. Dr. Mae-Wan Ho

A fully referenced version (to be published in Conference Proceedings) and handsomely illustrated power point presentation are available for download from ISIS online bookstore. Text version, Text and Presentation

Abstract and Introduction

In a paper published 30 years ago, Ho and Saunders (1979) proposed the then outrageous non-Darwinian idea that the intrinsic dynamics of developmental processes is the source of non-random variations that directs evolutionary change in the face of new environmental challenges; and the resulting evolutionary novelties are reinforced in successive generations through epigenetic mechanisms, independently of natural selection.

Our proposal has held up well against subsequent research findings, and is all the more relevant in view of the numerous molecular mechanisms discovered in epigenetic inheritance (Ho, 2009a,b) that could transmit developmental novelties to subsequent generations.

We have demonstrated how the nonlinear dynamics of living processes predicts the major features of macroevolution such as ‘punctuated equilibria’ (long period of stasis interrupted by abrupt changes); large changes from small critical disturbances, and discontinuous changes from continuously varying parameters; and why macroevolution of form and function is decoupled from the microevolution of gene sequences. We showed that the same (non-random) developmental changes are repeatedly produced by specific environmental stimuli. Furthermore, we demonstrated how general mathematical models can account for all the developmental transformations experimentally produced, which can make strong evolutionary predictions, and offer a natural taxonomy based on the predicted transformations.  

However,  neither the epigenetic mechanisms nor the dynamics of developmental processes are taken into account in the recent studies on evolution and development. 

The totality of research findings gives no support to the neo-Darwinian theory of evolution by the natural selection of random genetic mutations, nor to any theory ascribing putative differences in human attributes to genes. The overwhelming determinants of health and behaviour are social and environmental. Heredity is not in the genes, it is distributed over the entire web of nested organism-environment interrelationships extending from the social and ecological to the genetic and epigenetic. Consequently, there is no separation between development and evolution, and the organism actively participates in shaping its own development as well as the evolutionary future of the entire ecological community of which it is part.

Article first published 23/10/09

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