Mutação evolucionária aleatória: uma defesa da opinião consensual da Síntese Moderna

sábado, junho 14, 2014


Evolutionary Chance Mutation: A Defense of the Modern Synthesis’ Consensus View

Francesca Merlin, Department of Philosophy, University of Montréal, 2910 Edouard Montpetit Blvd, Québec, H3T 1G7 Canada.

e-mail: francesca.merlin@gmail.com.

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SUBJECT TERMS

Biased chance, Chance, Darwin, Directed mutation, Lamarckism, Modern synthesis, Mutator mechanism, Random mutation

Article Type: Article

Volume 2, September 2010


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Received 24 May 2010; Revised 28 July 2010; Accepted 12 August 2010

Abstract

One central tenet of the Modern Evolutionary Synthesis (1930s-1950s), and the consensus view among biologists until now, is that all genetic mutations occur by “chance” or at “random” with respect to adaptation. However, the discovery of some molecular mechanisms enhancing mutation rate in response to environmental conditions has given rise to discussions among biologists, historians and philosophers of biology about the “chance” vs “directed” character of mutations (1980s-2000s). In fact, some argue that mutations due to a particular kind of mutator mechanisms challenge the Modern Synthesis because they are produced when and where needed by the organisms concerned. This paper provides a defense of the Modern Synthesis’ consensus view about the chance nature of all genetic mutations by reacting to Jablonka and Lamb’s analysis of genetic mutations (2005) and the explicit Lamarckian flavor of their arguments. I argue that biologists can continue to talk about chance mutations according to what I call and define as the notion of “evolutionary chance,” which I claim is the Modern Synthesis’ consensus view and a reformulation of Darwin’s most influential idea of “chance” variation. Advances in molecular genetics are therefore significant but not revolutionary with respect to the Modern Synthesis’ paradigm.