Stochastic Linear Ornstein-Uhlenbeck Models for Comparative Hypotheses
Most phylogenetic comparative methods used for testing adaptive hypotheses make evolutionary assumptions that are not compatible with evolution of a trait towards an optimum. SLOUCH allows the user to estimate 1) the evolutionary and optimal regressions between a predictor and a response trait, and 2) phylogenetic inertia. These quantities are estimated jointly by a comparative method based upon an Ornstein-Uhlenbeck model of adaptive evolution in which a single trait adapts to an optimum that is influenced by one or more continuous, randomly changing predictor variables.
The biological, conceptual, and mathematical basis for SLOUCH is presented in A Comparative Method for Studying Adaptation to a Randomly Evolving Environment by Thomas F. Hansen, Jason Pienaar, and Steven Hecht Orzack, Evolution 62: 1965-1977 2008.
Please register for a free download of the SLOUCH program and the accompanying manual. SLOUCH is an R program and R must installed in order to run it (see the R project http://www.r-project.org/ for further details and a download of R.