Uses independent contrasts to estimate the evolutionary variance-covariance matrix for
n quantitative characters.
Usage
ic.sigma(phy, data, data.names=NULL)
Arguments
phy
Phylogenetic tree in 'phylo' format
data
Data matrix
data.names
Tip names for data vector that match tree species; ignored if data includes names
Value
Returns the estimated evolutionary variance-covariance matrix of the variables under a multivariate
Brownian motion model. If you have n characters in your analysis, this will be an nxn matrix.
Diagonal elements represent rate estimates for individual characters, while off-diagonal elements
represent the estimated covariance between two characters.
Details
Data for this function should be a matrix of continuously-valued variables.
References
Revell, L. J., L. J. Harmon, R. B. Langerhans, and J. J. Kolbe. 2007. A phylogenetic
approach to determining the importance of constraint on phenotypic evolution in the
neotropical lizard, Anolis cristatellus. Evolutionary Ecology Research 9: 261-282.