Mitigating Anticipated Effects of Systematic Errors Supports Sister-Group Relationship between Xenacoelomorpha and Ambulacraria
- Author(s)
- Hervé Philippe, Albert J. Poustka, Marta Chiodin, Katharina J. Hoff, Christophe Dessimoz, Bartlomiej Tomiczek, Philipp H. Schiffer, Steven Müller, Daryl Domman, Matthias Horn, Heiner Kuhl, Bernd Timmermann, Noriyuki Satoh, Tomoe Hikosaka-Katayama, Hiroaki Nakano, Matthew L. Rowe, Maurice R. Elphick, Morgane Thomas-Chollier, Thomas Hankeln, Florian Mertes, Andreas Wallberg, Jonathan P. Rast, Richard R. Copley, Pedro Martinez, Maximilian J. Telford
- Abstract
Xenoturbella and the acoelomorph worms (Xenacoelomorpha) are simple marine animals with controversial affinities. They have been placed as the sister group of all other bilaterian animals (Nephrozoa hypothesis), implying their simplicity is an ancient characteristic [1, 2]; alternatively, they have been linked to the complex Ambulacraria (echinoderms and hemichordates) in a clade called the Xenambulacraria [3–5], suggesting their simplicity evolved by reduction from a complex ancestor. The difficulty resolving this problem implies the phylogenetic signal supporting the correct solution is weak and affected by inadequate modeling, creating a misleading non-phylogenetic signal. The idea that the Nephrozoa hypothesis might be an artifact is prompted by the faster molecular evolutionary rate observed within the Acoelomorpha. Unequal rates of evolution are known to result in the systematic artifact of long branch attraction, which would be predicted to result in an attraction between long-branch acoelomorphs and the outgroup, pulling them toward the root [6]. Other biases inadequately accommodated by the models used can also have strong effects, exacerbated in the context of short internal branches and long terminal branches [7]. We have assembled a large and informative dataset to address this problem. Analyses designed to reduce or to emphasize misleading signals show the Nephrozoa hypothesis is supported under conditions expected to exacerbate errors, and the Xenambulacraria hypothesis is preferred in conditions designed to reduce errors. Our reanalyses of two other recently published datasets [1, 2] produce the same result. We conclude that the Xenacoelomorpha are simplified relatives of the Ambulacraria. Philippe et al. use new genetic data to study the phylogenetic affinities of the Xenacoelomorpha, a group of simple marine worms. Tackling potential sources of error strengthens support for a relationship between Xenacoelomorpha and the more complex echinoderms and hemichordates. The simple Xenacoelomorpha probably evolved from a complex ancestor.
- Organisation(s)
- Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science
- External organisation(s)
- University of Montreal, Max-Planck-Institut für molekulare Genetik, Dahlem Centre for Genome Research and Medical Systems Biology gGmbH, University of Barcelona, NYU Langone School of Medicine, University of Greifswald, University College London, Université de Lausanne, Swiss Institute of Bioinformatics, Leibniz-Institut für Gewässerökologie und Binnenfischerei, Okinawa Institute of Science and Technology Graduate University (OIST), Hiroshima University, National University Corporation Tsukuba University of Technology, Queen Mary University of London, Université de recherche Paris Sciences et Lettres, Johannes Gutenberg-Universität Mainz, Helmholtz-Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt, Uppsala University, Emory University, Centre National De La Recherche Scientifique (CNRS), Institució Catalana de Recerca i Estudis Avançats (ICREA), University of Gdańsk, Medical University of Gdańsk
- Journal
- Current Biology
- Volume
- 29
- Pages
- 1818-1826
- No. of pages
- 15
- ISSN
- 0960-9822
- DOI
- https://doi.org/10.1016/j.cub.2019.04.009
- Publication date
- 06-2019
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 106022 Microbiology
- Keywords
- ASJC Scopus subject areas
- General Agricultural and Biological Sciences, General Biochemistry,Genetics and Molecular Biology
- Sustainable Development Goals
- SDG 14 - Life Below Water
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/32f38941-554d-4b93-9e1b-aaf87cb87354