INVESTIGADORES
GIANNINI Norberto Pedro
artículos
Título:
Delayed-response phylogenetic correlation, an optimization-based method to test covariation of continuous characters
Autor/es:
GIANNINI, NP; GOLOBOFF, PA
Revista:
EVOLUTION
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Año: 2010 vol. 64 p. 1885 - 1898
ISSN:
0014-3820
Resumen:
A new phylogenetic comparative method is proposed, based on mapping two
continuous characters on a tree to generate data pairs for regression or
correlation analysis, which resolves problems of multiple character
reconstructions, phylogenetic dependence, and asynchronous responses
(evolutionary lags). Data pairs are formed in two ways (tree-down and
tree-up) by matching corresponding changes, x and y. Delayed responses
(y occurring later in the tree than x) are penalized by weighting pairs
using nodal or branch-length distance between x and y; immediate
(same-node) responses are given maximum weight. All combinations of
character reconstructions (or a random sample thereof) are used to find
the observed range of the weighted coefficient of correlation r (or
weighted slope b). This range is used as test statistic, and the null
distribution is generated by randomly reallocating changes (x and y) in
the topology. Unlike randomization of terminal values, this procedure
complies with Generalized Monte Carlo requirements while saving
considerable computation time. Phylogenetic dependence is avoided by
randomization without data transformations, yielding acceptable type-I
error rates and statistical power. We show that ignoring delayed
responses can lead to falsely non-significant results. Issues that arise
from considering delayed responses based on optimization are discussed.