Sudden origins: A general mechanism of evolution based on stress protein concentration and rapid environmental change

Authors

  • Bruno Maresca,

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    • Department of Pharmaceutical Sciences, University of Salerno, 84084 Fisciano, Salerno, Italy
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    • Dr. Maresca is a professor of biochemistry at the University of Salerno. He has worked out the role of membrane lipids and physical state in regulating heat shock gene expression with Laszlo Vigh and investigates the evolutionary mechanisms of temperature adaptation in Antarctic organisms

    • Both authors contributed equally to the article.

    • Fax: 39-089-96-28-28

  • Jeffrey H. Schwartz

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    • Both authors contributed equally to the article.

    • Dr. Schwartz is a professor of physical anthropology and history and philosophy of science at the University of Pittsburgh and research associate at the American Museum of Natural History. He recently published the first study of virtually the entire human fossil record (The Human Fossil Record series with I. Tattersall) and a revised edition of The Red Ape, which explores the assumptions underlying morphological and molecular approaches to phylogenetic reconstruction.


Abstract

A major theme in Darwinian evolutionary theory is that novelty arises through a process in which organisms and their features are gradually transformed. Morgan provided Darwinism and the evolutionary synthesis with the idea that minor mutations produce the minuscule morphological variations on which natural selection then acts, and that, although mutation is random, once a process of gradual genetic modification begins, it becomes directional and leads to morphological, and consequently organismal, transformation. In contrast, studies on the role of cell membrane physical states in regulating the expression of stress proteins in response to environmental shifts indicate the existence of a downstream mechanism that prevents or corrects genetic change (i.e., maintains “DNA homeostasis”). However, episodic spikes in various kinds of environmental stress that exceed an organism's cells' thresholds for expression of proper amounts of stress proteins responsible for protein folding (including stochastically occurring DNA repair) may increase mutation rate and genetic change, which in turn will alter the pattern of gene expression during development. If severe stress disrupts DNA homeostasis during meiosis (gametogenesis), this could allow for the appearance of significant mutational events that would otherwise be corrected or suppressed. In evolutionary terms, extreme spikes in environmental stress make possible the emergence of new genetic and consequent developmental and epigenetic networks, and thus also the emergence of potentially new morphological traits, without invoking geographic or other isolating mechanisms. Anat Rec (Part B: New Anat) 289B:38–46, 2006. © 2006 Wiley-Liss, Inc.

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