Support for a clade of Placozoa and Cnidaria in genes with minimal compositional bias

eLife

Harald Gruber-Vodicka¹  Ana Riesgo²  John C Marioni³  Vicki B Pearse⁴  Michael G Hadfield⁵  Christopher E Laumer⁶  Gonzalo Giribet⁶ 

[1] European Molecular Biology Laboratories-European Bioinformatics Institute, Hinxton, United Kingdom;Institute of Marine Sciences, University of California, Santa Cruz, United States;Invertebrate Division, Life Sciences Department, The Natural History Museum, London, United Kingdom;Kewalo Marine Laboratory, Pacific Biosciences Research Center and the University of Hawaii-Manoa, Honolulu, United States;Max Planck Institute for Marine Microbiology, Bremen, Germany;Wellcome Trust Sanger Institute, Hinxton, United Kingdom;

关键词: Placozoa;    Trichoplax;    Cnidaria;    Bilateria;    phylogeny;    compositional heterogeneity;   

DOI  :  10.7554/eLife.36278

来源: DOAJ

【 摘 要 】

The phylogenetic placement of the morphologically simple placozoans is crucial to understanding the evolution of complex animal traits. Here, we examine the influence of adding new genomes from placozoans to a large dataset designed to study the deepest splits in the animal phylogeny. Using site-heterogeneous substitution models, we show that it is possible to obtain strong support, in both amino acid and reduced-alphabet matrices, for either a sister-group relationship between Cnidaria and Placozoa, or for Cnidaria and Bilateria as seen in most published work to date, depending on the orthologues selected to construct the matrix. We demonstrate that a majority of genes show evidence of compositional heterogeneity, and that support for the Cnidaria + Bilateria clade can be assigned to this source of systematic error. In interpreting these results, we caution against a peremptory reading of placozoans as secondarily reduced forms of little relevance to broader discussions of early animal evolution.

【 授权许可】

Unknown