Evolution of functional specialization and division of labor
Claus Rueffler a,1, Joachim Hermisson a,b, and Günter P. Wagner c
aMathematics and Biosciences Group, Department of Mathematics, University of Vienna, 1090 Vienna, Austria;
bMax F. Perutz Laboratories, 1030 Vienna, Austria; and
cDepartment of Ecology and Evolutionary Biology and Yale Systems Biology Institute, Yale University, New Haven, CT 06520-8106
Edited by Michael Doebeli, University of British Columbia, Vancouver, BC, Canada, and accepted by the Editorial Board December 15, 2011 (received for review July 1, 2011)
Division of labor among functionally specialized modules occurs at all levels of biological organization in both animals and plants. Well-known examples include the evolution of specialized enzymes after gene duplication, the evolution of specialized cell types, limb diversification in arthropods, and the evolution of specialized colony members in many taxa of marine invertebrates and social insects. Here, we identify conditions favoring the evolution of division of labor by means of a general mathematical model. Our starting point is the assumption that modules contribute to two different biological tasks and that the potential of modules to contribute to these tasks is traded off. Our results are phrased in terms of properties of performance functions that map the phenotype of modules to measures of performance. We show that division of labor is favored by three factors: positional effects that predispose modules for one of the tasks, accelerating performance functions, and synergistic interactions between modules. If modules can be lost or damaged, selection for robustness can counteract selection for functional specialization. To illustrate our theory we apply it to the evolution of specialized enzymes coded by duplicated genes.
complexity, fitness landscape, saddle point
1To whom correspondence should be addressed. E-mail:firstname.lastname@example.org.
Author contributions: C.R., J.H., and G.P.W. designed research; C.R. performed research; and C.R., J.H., and G.P.W. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission. M.D. is a guest editor invited by the Editorial Board.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1110521109/-/DCSupplemental.
Freely available online through the PNAS open access option.