BAMMtools (version 2.1.12)

getCladeRates: Compute clade-specific mean rates

Description

Computes marginal clade-specific rates of speciation, extinction, or (if relevant) trait evolution from BAMM output.

Usage

getCladeRates(ephy, node = NULL, nodetype = "include", verbose = FALSE)

Value

A list with the following components:

• lambda: A vector of speciation rates (if applicable), with the i'th rate corresponding to the mean rate from the i'th sample in the posterior.

• mu: A vector of extinction rates (if applicable), with the i'th rate corresponding to the mean rate from the i'th sample in the posterior.

• beta: A vector of phenotypic rates (if applicable), with the i'th rate corresponding to the mean rate from the i'th sample in the posterior.

Arguments

ephy

An object of class bammdata.

node

If computing rates for a specific portion of tree, the node subtending the relevant subtree. If multiple nodes are supplied, then the equivalent number of nodetype must be supplied.

nodetype

Either "include" or "exclude". If nodetype = "include", the rates returned by the function will be for the subtree defined by node. If nodetype = "exclude", will compute mean rates for the tree after excluding the subtree defined by node. If multiple nodes are specified, there must be a nodetype for each node.

verbose

Logical. If TRUE, will print the sample index as mean rates are computed for each sample from posterior. Potentially useful for extremely large trees.

Author

Dan Rabosky

Details

Computes the time-weighted mean evolutionary rate for a given clade. Conversely, one can compute the rate for a given phylogeny while excluding a clade; this operation will give the "background" rate. It is important to understand several aspects of these mean rates. First, rates in the BAMM framework are not constant through time. Hence, the function computes the mean time-integrated rates across the subtree. Operationally, this is done by integrating the speciation rate with respect to time along each branch in the subtree. These time-integrated rates are then summed, and the sum is divided by the total sum of branch lengths for the subtree.

The function computes a rate for each sample in the posterior, and returns a list of rate vectors. Each rate in the corresponding vector is a mean rate for a particular sample from the posterior. Hence, you can think of the return value for this function as an estimate of the marginal distribution of rates for the focal clade. You can compute means, medians, quantiles, etc from these vectors.

References

http://bamm-project.org/

Examples

data(events.whales, whales)
ed <- getEventData(whales, events.whales, nsamples=500)
all_rates <- getCladeRates(ed)

mean(all_rates$lambda)
mean(all_rates$mu)
# joint density of mean speciation and extinction rates:
plot(all_rates$mu ~ all_rates$lambda)

# clade specific rates: here for Dolphin subtree:
dol_rates <- getCladeRates(ed, node=140)
mean(dol_rates$lambda)
mean(dol_rates$mu)

# defining multiple nodes
mean(getCladeRates(ed, node=c(132, 140),
     nodetype=c('include','exclude'))$lambda)