WELCOME TO TARDIGRADA 2018 14TH INTERNATIONAL SYMPOSIUM ON TARDIGRADA ABSTRACT BOOK Symposi nal um tio o a n n Ta r r te d n i I g r h a t d 4 a 1 COPENHAGEN BIOCENTER, DENMARK www.tardigrada2018.org U N I V E R S I T Y O F C O P E N H A G E N FACULTY OF SCIENCE 14th International Symposium on Tardigrada ABSTRACT BOOK Keynote talks………………………………………………………………………...…….…...…. 2-6 Oral presentations …………………………………...……………………………..………….… 7-61 Poster presentations ……………………………………………………………………......…. 62-136 List of participants .……………………………………………………..........................….…137-145 Tardigrada 2018 14th International Symposium on Tardigrada CHAIR Nadja Møbjerg (University of Copenhagen, Denmark) LOCAL COMMITTEE Hans Ramløv (Roskilde University, Denmark), Jesper Guldberg Hansen (University of Copenhagen, Denmark), Jette Eibye-Jacobsen (University of Copenhagen, Denmark/ Birkerød Gymnasium), Lykke Keldsted Bøgsted Hvidepil (University of Copenhagen, Denmark), Maria Kamilari (University of Copenhagen, Denmark), Reinhardt Møbjerg Kristensen (University of Copenhagen, Denmark), Thomas L. Sørensen-Hygum (University of Copenhagen, Denmark) FRONTPAGE The Symposium logo shows six individuals of Isoechiniscoides sifae drawn by Stine Elle. | 1 14th International Symposium on Tardigrada KEYNOTE TALKS | 2 14th International Symposium on Tardigrada Another round of animal phyogenetics: known, unknowns, needs Gonzalo Giribet Museum of Comparative Zoology, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA Background: Understanding animal phylogeny has been a hot topic through more than two centuries and a major focus for methodological developments in anatomical studies, cladistics, developmental biology, and molecular systematics. With the advent of new sequencing technologies, there has been a recent shift from using morphology or a handful of genes to genome- scale data, which can now be generated at an ever-increasing rate even from the smallest metazoans. The new data, however, come with new challenges associated with defining orthology, selecting genes and taxa for analyses, and in using automated ways to generate repeatable results. Results: New analyses have been conducted using genomes and Illumina-based transcriptomes to assemble the largest metazoan data set ever put together. Our data show novel results with respect to the position of taxa such as Placozoa and Chaetognatha and show the roadmap for how to approach difficult questions in animal evolution, including the phylogenies of Lophotrochozoa (a subtaxon of Spiralia) and Ecdysozoa. Many of these challenges are due to data heterogeneity, including compositional bias in key lineages. The difficulty in using comparative morphology to infer phylogenies across the metazoan phyla is also discussed. Conclusions: While the current round of analyses using improved datasets and optimized taxon sampling are able to resolve previous conflicting animal nodes, it is also clear that rate heterogeneity among members of a clade may pose a challenge for resolving certain nodes (e.g., the non-lophotrochozoan spiralians versus the lophotrochozoan ones). We also show that despite the enormous genomic resources in two lineages of Ecdysozoa (Arthropoda and Nematoda), phylogenies remain poorly resolved for this hyperdiverse lineage, especially due to limited genomic resources in most of the other ecdysozoan phyla, including Tardigrada. Keywords: Ecdysozoa, metazoan phylogeny, phylogenomics, Spiralia | 3 14th International Symposium on Tardigrada The rise of a tardigrade-unique toolbox for extremotolerance Takekazu Kunieda Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan Background: Tardigrades are a crowned animal group renowned for their resilience against various extreme environmental stresses. Since their discovery, the amazing tolerance records have fascinated researchers, but unfortunately some intrinsic features, such as the small size of tardigrades, the difficulty in rearing to a large quantity and easy contamination of other microorganisms, hindered progress of modern molecular biological approaches. In the past decade, the situation has changed progressively, with dramatic advances in the molecular dissection of tardigrade tolerance mechanisms, which has further accelerated in recent years. Results: Efforts to find the tolerance-related factors led to the identification of several tardigrade-unique protein families. The first category, novel heat-soluble proteins were discovered in line of searching for proteins with similar property to LEA proteins, which play important roles in desiccation-tolerant plant seeds and some anhydrobiotic animals. Till now, three classes of tardigrade-unique heat- soluble proteins, CAHS, SAHS and MAHS, have been identified and proposed to protect biomolecules from desiccation as LEA proteins do. The second category is a novel DNA protection protein dubbed Dsup. Dsup can associate with DNA in vitro and colocalize with nuclear DNA in animal cells. Human cultured cells engineered to express Dsup suffered much reduced DNA damage when exposed to X-ray irradiation or oxidative stress compared to unengineered control cells. Dsup-expressing cells also exhibited better survival and retention of proliferative ability after X-ray irradiation. Besides tardigrade-unique proteins, gene repertoire analyses revealed the specific expansion of some conserved stress-ameliorating genes and the characteristic loss of some metabolic and stress-signaling pathways. Although the proportion of foreign genes falls within the normal range of an animal genome, some of them are likely related to tolerance. Mimicking these features might be beneficial to improve the tolerance in other animals. Conclusions: Our current knowledge place tardigrade-unique proteins as important clues supporting the tolerance ability of tardigrades, even functional in mammalian cells. Recent comparative genome/transcriptome analyses among tardigrade species revealed the presence of many tardigrade-unique genes correlated with tolerability, representing a potential bountiful resource of tolerance genes awaiting future functional analyses. Future studies using other species, especially heterotardigrades, are essential to complement our molecular understanding of tardigrade resilience. The elucidation of tardigrade tolerance mechanisms would not only satisfy our scientific curiosity, but also contribute to develop new technology for medical and industrial applications. Keywords: DNA protection, Dsup, genome, heat soluble protein, tolerance mechanism | 4 14th International Symposium on Tardigrada Phylogenomics, gene families and the phylogenetic position of Tardigrada within Ecdysozoa Mark Blaxter1, Dominik Laetsch1, Lewis Stevens1, Georgios Koutsovoulos1, Sujai Kumar1, Kazuharu Arakawa2, Yuki Yoshida2, David Lunt3, Lutz Bachmann4, Łukasz Michalczyk5, Shinta Fujimoto6 1Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK, 2Keio Univeristy, Japan, 3Evolutionary Biology Group, University of Hull, Hull, UK, 4Natural History Museum, University of Oslo, Norway, 5Jagiellonian University, Kraków, Poland, 6Research Center for Marine Biology, Graduate School of Life Sciences, Tohoku University, Japan Background: The superphylum Ecdysozoa includes species-rich (Nematoda, Arthropoda) and species poor (Tardigrada, Nematomorpha, Kinorhynch and others) phyla, but collectively includes most of animal diversity. Morphological analyses and some molecular datasets place Tardigrada comfortably with Arthropoda and Onychophora within Panarthropoda, with Nematoidea (Nematoda plus Nematomorpha) sister to Panarthropoda. However, several phylogenomic analyses using multi- locus datasets have resolved Tardigrada as sister to Nematoidea. Whether this is an artefact of poor modelling of sequence change or a reflection of biological truth is unclear. Results: We have used genome-scale data from a range of ecdysozoans, including new genome and transcriptome data from many tardigrades, a kinorhynch and a nematomorph, to explore this question. We have used single-organism sequencing, or sequencing of populations of wild-isolated individuals to generate draft genome assemblies for previously unsampled taxa, in particularly using advanced tools to separate contaminants (food, microbiome) from the target species. As an example, using these approaches we have identified putative alphaproteobacterial symbionts of the kinorhynch Semnoderes armiger. From the proteomes predicted from the genomes and transcriptomes, we defined orthologue groups, and explored the patterns of protein family birth and loss between the phyla. Sequence-based phylogenetic analyses using single-copy orthologues yielded heterodox phylogenies associating Tardigrada with Nematoidea. However, gene family presence-absence analyses supported the traditional Tardigrada plus Arthropoda relationship. This pattern was not universal: for example, Tardigrada have lost some of the same core HOX genes that have also been lost in Nematoda. Conclusions: Analyses based on whole genomes disagree with phylogenetic analyses based on morphology alone. Whether this is because of inadequacies in our models of sequence evolution, because of unusual convergent patterns of gene gain, loss and change in different lineages, or because the true phylogeny differs from expectations, it is clear that the internal structure of Ecdysozoa, and the phylogenetic position of the Tardigrada, remains an exciting area for investigation.