Document Type

Article

Publication Date

6-25-2011

Abstract

Emerging concepts in developmental biology, such as facilitated variation and dynamical patterning modules, address a major shortcoming of the Modern Synthesis in Biology: how genotypic variation is transduced into functional yet diverse phenotypic variation. Still, we lack a theory to explain how variation at the cellular and tissue level is coordinated into variation at the whole-organism level, especially as priority of cellular and tissue functions change over an individual’s lifetime and are influenced by environmental variation. Here, we propose that interactions among a limited subset of physiological factors that we call, integrators, regulate most phenotypic variation at the organismal level. Integrators are unique among physiological factors in that they have the propensity to coordinate the expression of conserved gene modules of most types of tissues because they participate as nodes in a hierarchical network. In other words, integrator networks impose physiological epistasis, meaning that whole-organism phenotypic responses will be influenced by previous experiences, current environmental conditions, and fitness priorities as encoded by individual integrators. Below, we provide examples of how integrator networks are responsible for both profound and irreversible phenotypic changes (i.e., metamorphosis, sexual differentiation) as well as subtler, transient (e.g., pelage color, seasonal fluctuations in lymphoid and reproductive tissues) variation. The goal of this article is not to describe completely how integrator networks function, but to stimulate discussion about the role of physiology in linking genetic to phenotypic variation. To generate useful data sets for understanding integrator networks and to inform whole-organism physiology generally, we describe several useful tools including vector-field editing, response-surface regression, and experiments of life-table responses. We then close by highlighting some implications of integrator networks for conservation and biomedicine.

Comments

Alt. Title "Integrator Networks: Illuminating the Black Box Linking Genotype and Phenotype"

From the symposium "Bridging the Gap Between Ecoimmunology and Disease Ecology" presented at the annual meeting of the Society for Integrative and Comparative Biology, January 3-7, 2011, at Salt Lake City, Utah.

Additional Copyright: The Author 2011. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Citation / Publisher Attribution

Lynn B. Martin,1, Andrea L. Liebl, Justin H. Trotter, Christina L. Richards, Krista McCoy, and Michael W. McCoy
Integrative and Comparative Biology, v 51(4)p.514-
527 doi:10.1093/icb/icr049

MMartin_table_1_suppl.rtf (154 kB)
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MMartin_table_2_suppl.rtf (120 kB)
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Additional Files

MMartin_table_1_suppl.rtf (154 kB)
Table 1

MMartin_table_2_suppl.rtf (120 kB)
Table 2

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