Xenacoelomorpha Survey Reveals That All 11 Animal Homeobox Gene Classes Were Present in the First Bilaterians

Brauchle, Michael Anton; Bilican, Adem; Eyer, Claudia; Bailly, X; Martinez, P; Ladurner, P; Bruggmann, Rémy; Sprecher, SG (2018). Xenacoelomorpha Survey Reveals That All 11 Animal Homeobox Gene Classes Were Present in the First Bilaterians. Genome biology and evolution, 10(9), pp. 2205-2217. Oxford University Press 10.1093/gbe/evy170

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Homeodomain transcription factors are involved in many developmental processes across animals and have been linked to body plan evolution. Detailed classifications of these proteins identified 11 distinct classes of homeodomain proteins in animal genomes, each harboring specific sequence composition and protein domains. Although humans contain the full set of classes, Drosophila melanogaster and Caenorhabditis elegans each lack one specific class. Furthermore, representative previous analyses in sponges, ctenophores, and cnidarians could not identify several classes in those nonbilaterian metazoan taxa. Consequently, it is currently unknown when certain homeodomain protein classes first evolved during animal evolution. Here, we investigate representatives of the sister group to all remaining bilaterians, the Xenacoelomorpha. We analyzed three acoel, one nemertodermatid, and one Xenoturbella transcriptomes and identified their expressed homeodomain protein content. We report the identification of representatives of all 11 classes of animal homeodomain transcription factors in Xenacoelomorpha and we describe and classify their homeobox genes relative to the established animal homeodomain protein families. Our findings suggest that the genome of the last common ancestor of bilateria contained the full set of these gene classes, supporting the subsequent diversification of bilaterians.

Item Type:

Journal Article (Original Article)


08 Faculty of Science > Department of Biology > Institute of Cell Biology
08 Faculty of Science > Department of Biology > Bioinformatics and Computational Biology

UniBE Contributor:

Brauchle, Michael Anton, Bilican, Adem, Eyer, Claudia, Bruggmann, Rémy


500 Science > 570 Life sciences; biology
500 Science > 590 Animals (Zoology)




Oxford University Press




Michael Anton Brauchle

Date Deposited:

27 Dec 2018 14:38

Last Modified:

05 Dec 2022 15:22

Publisher DOI:






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