Phylogenetic targeting


Arnold, C., Nunn, C. L. 2010. Phylogenetic Targeting of Research Effort in Evolutionary Biology. American Naturalist 176:601-612. [PDF]

Project Description:

Here, I will introduce one of my previous research projects, Phylogenetic Targeting, which is more fully described in the official publication and in my Master's thesis [pdf]. For more information and a web implementation of the program, see In what follows, we provide an abstract of the project.

Many questions in comparative biology require that new data be collected, either to build a comparative database for the first time or to augment existing data. Given resource limitations in collecting data, which species should be studied to increase the size of comparative data sets? By taking the hypotheses, other comparative data relevant to the hypotheses, and an estimate of phylogeny, we show that a method of phylogenetic targeting can systematically identify the species that offer the greatest statistical power to test the hypotheses. Phylogenetic targeting selects potential candidates for future data collection based on a flexible scoring system that maximizes the differences in pairwise comparisons. The method can control for confounding variables, or it can maximize the power to test competing hypotheses. We used simulations to assess the performance of phylogenetic targeting, as compared to a less systematic approach of randomly selecting species (as might occur when data have been collected on species without regard to variation in the traits of interest). The simulations revealed that selection of species using phylogenetic targeting increases the statistical power to detect correlations and that power increases with the number of species in the clade even when the number of samples collected was not increased. We also developed a web-based, freely available and publicly accessible computer program PhyloTargeting that implements the approach. It provides a user-friendly interface, a variety of options to analyze the data set, and graphical visualizations of the results.