Campus Units

Ecology, Evolution and Organismal Biology, Statistics

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

11-2016

Journal or Book Title

Evolution

Volume

70

Issue

11

First Page

2623

Last Page

2631

DOI

10.1111/evo.13045

Abstract

Evolutionary morphologists frequently wish to understand the extent to which organisms are integrated, and whether the strength of morphological integration among subsets of phenotypic variables differ among taxa or other groups. However, comparisons of the strength of integration across datasets are difficult, in part because the summary measures that characterize these patterns (RV and rPLS) are dependent both on sample size and on the number of variables. As a solution to this issue we propose a standardized test statistic (a z-score) for measuring the degree of morphological integration between sets of variables. The approach is based on a partial least squares analysis of trait covariation, and its permutation-based sampling distribution. Under the null hypothesis of a random association of variables, the method displays a constant expected value and confidence intervals for datasets of differing sample sizes and variable number, thereby providing a consistent measure of integration suitable for comparisons across datasets. A two-sample test is also proposed to statistically determine whether levels of integration differ between datasets, and an empirical example examining cranial shape integration in Mediterranean wall lizards illustrates its use. Some extensions of the procedure are also discussed.

Comments

This is the peer reviewed version of the following article: Adams, D. C. and Collyer, M. L. (2016), On the comparison of the strength of morphological integration across morphometric datasets. Evolution, 70: 2623–2631, which has been published in final form at doi: 10.1111/evo.13045. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.

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Copyright Owner

The Authors

Language

en

File Format

application/pdf

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