A simple model of the relationship between asymmetry and developmental stability

Authors

  • Houle

    1. Department of Zoology, University of Toronto, Toronto, Ontario M5S 3G5, CANADA, and Department of Biological Science, Florida State University, Tallahassee, FL 32306–1100, USA
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David Houle Department of Biological Science, Florida State University, Tallahassee, FL 32306–1100, USA. Tel.: +1 850 645 0388; fax: +1 850 644 9829; e-mail: dhoule@bio.fsu.edu

Abstract

The relationship between developmental stability and morphological asymmetry is derived under the standard view that structures on each side of an individual develop independently and are normally distributed. I use developmental variance of sizes of parts, VD, as the converse of developmental stability, and assume that VD follows a gamma distribution. Repeatability of asymmetry, a measure of how informative asymmetry is about VD, is quite insensitive to the variance in VD, for example only reaching 20% when the coefficient of variation of VD is 100%. The coefficient of variation of asymmetry, CVFA, also increases very slowly with increasing population variation in VD. CVFA values from empirical data are sometimes over 100%, implying that developmental stability is sometimes more variable than any previously studied type of trait. This result suggests that alternatives to this model may be needed.

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