Diversity and Evolution of Paramoeba spp. and their Kinetoplastid Endosymbionts |
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Authors: | Shannon J Sibbald Ugo Cenci Morgan Colp Yana Eglit Charles J O'Kelly John M Archibald |
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Institution: | 1. Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada;2. Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, NS, Canada;3. Department of Biology, Dalhousie University, Halifax, NS, Canada;4. Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, USA;5. Canadian Institute for Advanced Research, CIFAR Program in Integrated Microbial Biodiversity, Toronto, ON, Canada |
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Abstract: | Members of the genus Paramoeba (including Neoparamoeba) (Amoebozoa) are single‐celled eukaryotes of economic and ecological importance because of their association with disease in a variety of marine animals including fish, sea urchins, and lobster. Interestingly, they harbor a eukaryotic endosymbiont of kinetoplastid ancestry, Perkinsela sp. To investigate the complex relationship between Paramoeba spp. and Perkinsela sp., as well as the relationships between different Paramoeba species, molecular data was obtained for four novel isolates. We also acquired new data from the urchin pathogen P. invadens. Comprehensive molecular phylogenetic analyses were carried out using 33 newly obtained 18S rDNA sequences from the host amoebae and 16 new 18S rDNA sequences from their corresponding Perkinsela sp., together with all publicly available 18S molecular data. Intra‐isolate 18S rDNA nucleotide diversity was found to be surprisingly high within the various species of Paramoeba, but relatively low within their Perkinsela sp. endosymbionts. 18S rDNA phylogenies and ParaFit co‐evolution analysis revealed a high degree of congruence between the Paramoeba and Perkinsela sp. tree topologies, strongly suggesting that a single endosymbiotic event occurred in the common ancestor of known Paramoeba species, and that the endosymbionts have been inherited vertically ever since. |
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Keywords: | Amoebic gill disease co‐evolution endosymbiosis genome evolution Kinetoplastea Perkinsela sp phylogeny ribosomal DNA |
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