Simulate the (independent) evolution of one or several continuous
characters along a given phylogenetic tree under a homogeneous
Brownian model.
Usage
evolve.phylo(phy, value, var)
Arguments
phy
an object of class 'phylo' with branch lengths.
value
ancestral states, one by character. The (optional) names
of this vector will be used as character names.
var
the variance of each character.
Value
An object of class 'ancestral', inheriting from the 'phylo' class. The
following components are added:
node.charactera data.frame with node ids as rownames and one
column by character, containing all the inner node values for each
character.
tip.charactera data.frame with tip ids as rownames and one
column by character, containing all the tip values for each
character.
Details
Let x be a continuous character.
If it evolves according to a Brownian model, its value at time t follows a normal law with mean x0 and variance t*sigma_x,
where x0 is the value of the character at time 0, and sigma_x is the 'inner' variance of the character.
The evolution of a continuous character is performed by letting the character evolve on each branch, from its ancestral root state.
The final state of a branch is the ancestral states of the daughter branches, and so on.