Analysis of Environmental 18S Ribosomal RNA Sequences reveals Unknown Diversity of the Cosmopolitan Phylum Telonemia

• Published in: Protist
• Main Authors: Shalchian-Tabrizi, Kamran, Kauserud, Håvard, Massana, Ramon, Klaveness, Dag, Jakobsen, Kjetill S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2007
• Subjects: 18S rDNA; Environmental sequences; Telonema; Telonemia; Phylogeny; Indian; Antarc*
• Online Access: http://hdl.handle.net/10261/26734; https://doi.org/10.1016/j.protis.2006.10.003

8 pages, 2 figures, 1 table Telonemia has recently been described as a new eukaryotic phylum with uncertain evolutionary origin. So far, only two Telonemia species, Telonema subtilis and Telonema antarcticum, have been described, but there are substantial variations in size and morphology among Telonema isolates and field observations, indicating a hidden diversity of Telonemia-like species and populations. In this study, we investigated the diversity and the global distribution of this group by analyzing 18S rDNA sequences from marine environmental clone libraries published in GenBank as well as several unpublished sequences from the Indian Ocean. Phylogenetic analyses of the identified sequences suggest that the Telonemia phylum includes several undescribed 18S rDNA phylotypes, probably corresponding to a number of different species and/or populations. The Telonemia phylotypes form two main groups, here referred to as Telonemia Groups 1 and 2. Some of the closely related sequences originate from separate oceans, indicating worldwide distributions of various Telonemia phylotypes, while other phylotypes seem to have limited geographical distribution. Further investigations of the evolutionary relationships within Telonemia should be conducted on isolated cultures of Telonema-like strains using multi-locus sequencing and morphological data This work was supported by the Norwegian Research Council to KSJ (No. 166555 and 159822) and a grant from the French GIS (PICOCEAN) Peer reviewed