title: Mitogenomics reveals phylogeny and repeated motifs in control regions of the deep-sea family Siboglinidae (Annelida).
abstract: Deep-sea tubeworms in the annelid family Siboglinidae have drawn considerable interest regarding their ecology and evolutionary biology. As adults, they lack a digestive tract and rely on endosymbionts for nutrition. Moreover, they are important members of chemosynthetic environments including hydrothermal vents, cold seeps, muddy sediments, and whale bones. Evolution and diversification of siboglinids has been associated with host-symbiont relationships and reducing habitats. Despite their importance, the taxonomy and phylogenetics of this clade are debated due to conflicting results. In this study, 10 complete and 2 partial mitochondrial genomes and one transcriptome were sequenced and analyzed to address siboglinid evolution. Notably, repeated nucleotide motifs were found in control regions of these mt genomes, which may explain previous challenges of sequencing siboglinid mt genomes. Phylogenetic analyses of amino acid and nucleotide datasets were conducted in order to infer evolutionary history. Both analyses generally had strong nodal support and suggest Osedax is most closely related to the Vestimentifera+Sclerolinum clade, rather than Frenulata, as recently reported. These results imply Osedax, the only siboglinid lineage with heterotrophic endosymbionts, evolved from a lineage utilizing chemoautotrophic symbionts.
authors.affiliation: Department of Biological Sciences & Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, AL 36849, USA. Electronic address: yzl0084@auburn.edu.
authors.forename: Yuanning
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Biological Sciences & Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, AL 36849, USA; School of Biological Sciences, University of Queensland, St. Lucia, QLD 4067, Australia. Electronic address: k.kocot@uq.edu.au.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Kocot
authors.affiliation: University of Bergen Museum, N-5020 Bergen, Norway.
authors.forename: Christoffer
authors.initials: C
authors.lastname: Schander
authors.affiliation: Department of Biological Sciences & Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, AL 36849, USA. Electronic address: santos@auburn.edu.
authors.forename: Scott R
authors.initials: SR
authors.lastname: Santos
authors.affiliation: Department of Biological Sciences & Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, AL 36849, USA. Electronic address: thornhill.dan@gmail.com.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Thornhill
authors.affiliation: Department of Biological Sciences & Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, AL 36849, USA. Electronic address: ken@auburn.edu.
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Halanych
mesh_terms: D000818:Animals; D005075:Biological Evolution; D004272:DNA, Mitochondrial / Q000235:genetics; D017753:Ecosystem; D054629:Genome, Mitochondrial; D010802:Phylogeny; D011077:Polychaeta / Q000145:classification* / Q000235:genetics; D017422:Sequence Analysis, DNA; D013559:Symbiosis; D059467:Transcriptome
chemical_list: D004272:DNA, Mitochondrial
keywords: Control region; Mitogenomic; Osedax; Size variations