Three tree priors and five datasets

Abstract

Abstract The age of the root of the Indo-European language family has received much attention since the application of Bayesian phylogenetic methods by Gray and Atkinson (2003). With the application of new models, the root age of the Indo-European family has tended to decrease from an age that supported the Anatolian origin hypothesis to an age that supports the Steppe origin hypothesis (Chang et al., 2015). However, none of the published work in Indo-European phylogenetics has studied the effect of tree priors on phylogenetic analyses of the Indo-European family. In this paper, I intend to fill this gap by exploring the effect of tree priors on different aspects of the Indo-European family’s phylogenetic inference. I apply three tree priors—Uniform, Fossilized Birth-Death (FBD), and Coalescent—to five publicly available datasets of the Indo-European language family. I evaluate the posterior distribution of the trees from the Bayesian analysis using Bayes Factor, and find that there is support for the Steppe origin hypothesis in the case of two tree priors. I report the median and 95 % highest posterior density (HPD) interval of the root ages for all three tree priors. A model comparison suggests that either the Uniform prior or the FBD prior is more suitable than the Coalescent prior to the datasets belonging to the Indo-European language family.