Thank you all for your ideas. I'll probably explore further Liam's method.
sincerely,
john
On Tue, Mar 12, 2013 at 5:33 PM, Liam J. Revell liam.rev...@umb.edu wrote:
I did a little further exploration of this proposed method - the results
discussion are here:
Hi All,
Just a follow up on this. I was thinking about what Liam suggested, and I
think it's a different test to what I suggested, but maybe I'm wrong.
In particular, Liam's using squared contrasts in y, so that's asking
whether the absolute size of changes in y depends on x at the ancestral
Hi Rob -
Regarding your comment: However, I think that this test is not quite
the same as asking whether the rate of evolution of y depends on x. For
example, it's possible you could (correctly) see a relationship with
Liam's test even if there was no relationship between the rate of
Hi Liam,
I think you're right, and I'm wrong.
I included the reference below, which I left out of the last email.
Rob
[1] Freckleton, R.P. (2000) Phylogenetic tests of ecological and
evolutionary hypotheses: checking for phylogenetic independence. Funct.
Ecol. 14, 129134
On 16 March 2013
Rob Lanfear wrote:
In particular, Liam's using squared contrasts in y, so that's
asking whether the absolute size of changes in y depends on
x at the ancestral node. I might have missed something here,
but that sounds very similar in principle to Freckleton's
test of whether the
Hi there,
My one-euro contribution.
Another approach can be the following one:
-you rescale the branch lenghts of your tree while keeping its topology
constant based on the pairwise (triangular) matrix of range size
differences (or range overlaps, whatever metric you choose). This tree
rescaling
Hi All,
I have simpler, probably worse, and possibly useless suggestion. You could
borrow from the rates of molecular evolution literature to do this. We
often want to answer exactly these kinds of question, where the dependent
variable is the rate of evolution, rather than range size. So,
I did a little further exploration of this proposed method - the
results discussion are here:
http://blog.phytools.org/2013/03/investigating-whether-rate-of-one.html
Maybe this will be of some help in deciding the best approach to go
forward with.
All the best, Liam
Liam J. Revell,
John,
This is a tricky question. If your independent variables were discrete, you
could use a stochastic character mapping approach to map state regimes
onto your tree and ask whether the regimes had different rates using a
model selection approach. (This could be done with the R packages
Hi John Matt.
What about the admittedly ad hoc approach of computing the correlation
between the states at ancestral nodes for x the squared contrasts for
corresponding nodes for y? Then you can generate a null distribution for
the test statistic (say, a Pearson or Spearman rank
10 matches
Mail list logo
