LOW GENETIC VARIABILITY OF SARGASSUM MUTICUM (PHAEOPHYCEAE) REVEALED BY A GLOBAL ANALYSIS OF NATIVE AND INTRODUCED POPULATIONS1 |
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Authors: | Chi Chiu Cheang Ka Hou Chu Daisuke Fujita Goro Yoshida Masanori Hiraoka Alan Critchley Han Gil Choi Delin Duan Yukihiko Serisawa Put O Ang Jr |
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Institution: | 1. Simon F. S. Li Marine Science Laboratory, Department of Biology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China;2. Department of Marine Biosciences, Tokyo University of Marine Science and Technology, Tokyo, 108‐8477, Japan;3. National Research Institute of Fisheries and Environment of Inland Sea, Hiroshima, 739‐0452, Japan;4. Usa Marine Biological Institute, Kochi University, Kochi, 781‐1164, Japan;5. Acadian Seaplants Limited, Dartmouth, Nova Scotia, Canada B3B 1X8;6. Faculty of Biological Science and Research, Wonkwang University, Iksan 570‐749, Korea;7. Institute of Oceanology, The Chinese Academy of Sciences, Qingdao, 266071, China;8. Faculty of Education and Human Sciences, University of Yamanashi, Yamanashi 400‐8510, Japan;9. Author for correspondence: e‐mail . |
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Abstract: | Sargassum muticum (Yendo) Fensholt is one of the most well‐known invasive species in the world. There have, however, been few genetic investigations on both its introduced and native populations. There are also some questions about the taxonomic status of this species. This study is the first to assess the genetic diversity of S. muticum on a global scale, by utilizing one marker each from the extranuclear genomes, namely, plastidial RUBISCO and mitochondrial TrnW_I spacers, as well as the nuclear internal transcribed spacer 2 (ITS2). Based on the markers investigated, both the invasive as well as the native populations of this species appeared very homogenous, when compared with other invasive and brown macroalgae. No variation in ITS2 and RUBISCO spacer was revealed in S. muticum populations, including those from its native ranges in Asia and the introduced ranges in Europe and North America. Two TrnW_I spacer haplotypes with a fixed two‐nucleotide difference were found between the populations of eastern Japan and the other 15 populations examined. This study confirms that there is no cryptic diversity in the introduced range of this species. All the materials collected globally are indeed S. muticum. Results depicting the distribution range of the two TrnW_I spacer haplotypes also support the earlier suggestion that the source of the introduced S. muticum populations is most likely western and central Japan (Seto Inland Sea), where the germlings of S. muticum were likely to have been transported with the Pacific oysters previously introduced for farming in Canada, UK, and France in earlier years. |
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Keywords: | genetic diversity internal transcribed spacer 2 (ITS2) invasion Pacific oyster RUBISCO spacer Sargassum muticum TrnW_TrnI spacer |
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