Marc Kirschner*,† and John Gerhart‡
-Author Affiliations
*Department of Cell Biology, Harvard Medical School, Boston, MA 02115; and ‡Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
Contributed by John C. Gerhart
Abstract
Evolvability is an organism’s capacity to generate heritable phenotypic variation. Metazoan evolution is marked by great morphological and physiological diversification, although the core genetic, cell biological, and developmental processes are largely conserved. Metazoan diversification has entailed the evolution of various regulatory processes controlling the time, place, and conditions of use of the conserved core processes. These regulatory processes, and certain of the core processes, have special properties relevant to evolutionary change. The properties of versatile protein elements, weak linkage, compartmentation, redundancy, and exploratory behavior reduce the interdependence of components and confer robustness and flexibility on processes during embryonic development and in adult physiology. They also confer evolvability on the organism by reducing constraints on change and allowing the accumulation of nonlethal variation. Evolvability may have been generally selected in the course of selection for robust, flexible processes suitable for complex development and physiology and specifically selected in lineages undergoing repeated radiations.
Footnotes
↵ † To whom reprint requests should be addressed. e-mail:marc@hms.harvard.edu.
A commentary on this article begins on page 8417.
ABBREVIATIONS:
SOP,sensory organ precursor;MT,microtubule;3-D,three dimensional;CAM,cell adhesion molecule
Copyright © 1998, The National Academy of Sciences
Copyright © 1998, The National Academy of Sciences
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