Interspecies correlation for neutrally evolving traits

JOURNAL OF THEORETICAL BIOLOGY

卷:309

Article

Bartoszek, Krzysztof¹ 

[1] Chalmers Univ Technol, S-41296 Gothenburg, Sweden

关键词: Phylogenetic comparative methods;    Birth and death process;    Conditioned branching process;    Branching Brownian motion;    Uncertainty in phylogeny;   

DOI  :  10.1016/j.jtbi.2012.06.008

来源: Elsevier

【 摘 要 】

A simple way to model phenotypic evolution is to assume that after splitting, the trait values of the sister species diverge as independent Brownian motions. Relying only on a prior distribution for the underlying species tree (conditioned on the number, n, of extant species) we study the random vector (X-1, ... , X-n) of the observed trait values. In this paper we derive compact formulae for the variance of the sample mean and the mean of the sample variance for the vector (X-1, ... , X-n). The key ingredient of these formulae is the correlation coefficient between two trait values randomly chosen from (X-1,X- ... , X-n). This interspecies correlation coefficient takes into account not only variation due to the random sampling of two species out of n and the stochastic nature of Brownian motion but also the uncertainty in the phylogenetic tree. The latter is modeled by a (supercritical or critical) conditioned branching process. In the critical case we modify the Aldous-Popovic model by assuming a proper prior for the time of origin. (C) 2012 Elsevier Ltd. All rights reserved.

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