Dear Karla.
What do you want to use fitContinuous to do?
fitContinuous fits multiple models, some of which will result in low
values of lambda in a test of phylogenetic signal. In fact, this is
really the main point of fitContinuous: to compare alternative models
for trait evolution. If you just want to estimate the most-likely rate
of evolution assuming a Brownian evolutionary process, you could just
compute the mean squared PIC value (this is the REML estimate of sigma^2).
fitContinuous can also take into account sampling error in the
estimation of species means, which can be a cause for low measured
values of phylogenetic signal.
Hope this is of some help Karla.
All the best, Liam
Liam J. Revell
University of Massachusetts Boston
Universidad Católica de la Ssma Concepción
web: http://faculty.umb.edu/liam.revell/, http://www.phytools.org
Academic Director UMass Boston Chile Abroad:
https://www.umb.edu/academics/caps/international/biology_chile
On 9/23/2020 8:21 PM, Karla Shikev wrote:
[EXTERNAL SENDER]
Dear friends,
I guess this is as much a philosophical question as it is methodological. I
want to estimate the rate of evolution of a trait (e.g. using the
fitContinuous function), but the trait has low phylogenetic signal (e.g.
lambda close to 0). Does it make sense to use fitContinuous on a trait
evolving like that?
Thanks for your input.
Karla
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