title: Simultaneously estimating evolutionary history and repeated traits phylogenetic signal: applications to viral and host phenotypic evolution.
abstract: Phylogenetic signal quantifies the degree to which resemblance in continuously-valued traits reflects phylogenetic relatedness. Measures of phylogenetic signal are widely used in ecological and evolutionary research, and are recently gaining traction in viral evolutionary studies. Standard estimators of phylogenetic signal frequently condition on data summary statistics of the repeated trait observations and fixed phylogenetics trees, resulting in information loss and potential bias. To incorporate the observation process and phylogenetic uncertainty in a model-based approach, we develop a novel Bayesian inference method to simultaneously estimate the evolutionary history and phylogenetic signal from molecular sequence data and repeated multivariate traits. Our approach builds upon a phylogenetic diffusion framework that model continuous trait evolution as a Brownian motion process and incorporates Pagel'sλtransformation parameter to estimate dependence among traits. We provide a computationally efficient inference implementation in the BEAST software package. We evaluate the synthetic performance of the Bayesian estimator of phylogenetic signal against standard estimators, and demonstrate the use of our coherent framework to address several virus-host evolutionary questions, including virulence heritability for HIV, antigenic evolution in influenza and HIV, and Drosophila sensitivity to sigma virus infection. Finally, we discuss model extensions that will make useful contributions to our flexible framework for simultaneously studying sequence and trait evolution.
authors.affiliation: Department of Microbiology and Immunology, Rega Institute, KU Leuven - University of Leuven, Leuven, Belgium.
authors.forename: Bram
authors.initials: B
authors.lastname: Vrancken
authors.affiliation: Department of Microbiology and Immunology, Rega Institute, KU Leuven - University of Leuven, Leuven, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Lemey
authors.affiliation: Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK ; Fogarty International Center, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Rambaut
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
authors.forename: Trevor
authors.initials: T
authors.lastname: Bedford
authors.affiliation: Department of Genetics, University of Cambridge, Cambridge, UK.
authors.forename: Ben
authors.initials: B
authors.lastname: Longdon
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Zürich, University of Zürich, Zürich, Switzerland.
authors.forename: Huldrych F
authors.initials: HF
authors.lastname: Günthard
authors.affiliation: Departments of Biomathematics and Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095-1766, USA ; Department of Biostatistics, UCLA Fielding School of Public Health, University of California, Los Angeles, CA 90095-1766, USA.
authors.forename: Marc A
authors.initials: MA
authors.lastname: Suchard
keywords: Bayesian phylogenetics; adaptation; comparative approach; virulence; virus evolution