title: AQUATIC PLANT SPECIATION AFFECTED BY DIVERSIFYING SELECTION OF ORGANELLE DNA REGIONS(1).
abstract: Many of the genes that control photosynthesis are carried in the chloroplast. These genes differ among species. However, evidence has yet to be reported revealing the involvement of organelle genes in the initial stages of plant speciation. To elucidate the molecular basis of aquatic plant speciation, we focused on the unique plant species Chara braunii C. C. Gmel. that inhabits both shallow and deep freshwater habitats and exhibits habitat-based dimorphism of chloroplast DNA (cpDNA). Here, we examined the "shallow" and "deep" subpopulations of C. braunii using two nuclear DNA (nDNA) markers and cpDNA. Genetic differentiation between the two subpopulations was measured in both nDNA and cpDNA regions, although phylogenetic analyses suggested nuclear gene flow between subpopulations. Neutrality tests based on Tajima's D demonstrated diversifying selection acting on organelle DNA regions. Furthermore, both "shallow" and "deep" haplotypes of cpDNA detected in cultures originating from bottom soils of three deep environments suggested that migration of oospores (dormant zygotes) between the two habitats occurs irrespective of the complete habitat-based dimorphism of cpDNA from field-collected vegetative thalli. Therefore, the two subpopulations are highly selected by their different aquatic habitats and show prezygotic isolation, which represents an initial process of speciation affected by ecologically based divergent selection of organelle genes.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanResearch Program for Computational Science, Riken, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, JapanCenter for Interdisciplinary Research, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanFunabashi Shibayama High School, 7-39-1 Shibayama, Funabashi, Chiba 274-0816, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanNational Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-0053, JapanDepartment of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanDepartment of Oceans Sciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Syou
authors.initials: S
authors.lastname: Kato
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanResearch Program for Computational Science, Riken, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, JapanCenter for Interdisciplinary Research, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanFunabashi Shibayama High School, 7-39-1 Shibayama, Funabashi, Chiba 274-0816, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanNational Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-0053, JapanDepartment of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanDepartment of Oceans Sciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Kazuharu
authors.initials: K
authors.lastname: Misawa
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanResearch Program for Computational Science, Riken, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, JapanCenter for Interdisciplinary Research, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanFunabashi Shibayama High School, 7-39-1 Shibayama, Funabashi, Chiba 274-0816, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanNational Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-0053, JapanDepartment of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanDepartment of Oceans Sciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Takahashi
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanResearch Program for Computational Science, Riken, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, JapanCenter for Interdisciplinary Research, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanFunabashi Shibayama High School, 7-39-1 Shibayama, Funabashi, Chiba 274-0816, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanNational Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-0053, JapanDepartment of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanDepartment of Oceans Sciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Sakayama
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanResearch Program for Computational Science, Riken, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, JapanCenter for Interdisciplinary Research, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanFunabashi Shibayama High School, 7-39-1 Shibayama, Funabashi, Chiba 274-0816, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanNational Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-0053, JapanDepartment of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanDepartment of Oceans Sciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Satomi
authors.initials: S
authors.lastname: Sano
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanResearch Program for Computational Science, Riken, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, JapanCenter for Interdisciplinary Research, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanFunabashi Shibayama High School, 7-39-1 Shibayama, Funabashi, Chiba 274-0816, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanNational Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-0053, JapanDepartment of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanDepartment of Oceans Sciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Kosuge
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanResearch Program for Computational Science, Riken, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, JapanCenter for Interdisciplinary Research, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanFunabashi Shibayama High School, 7-39-1 Shibayama, Funabashi, Chiba 274-0816, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanNational Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-0053, JapanDepartment of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanDepartment of Oceans Sciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Fumie
authors.initials: F
authors.lastname: Kasai
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanResearch Program for Computational Science, Riken, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, JapanCenter for Interdisciplinary Research, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanFunabashi Shibayama High School, 7-39-1 Shibayama, Funabashi, Chiba 274-0816, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanNational Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-0053, JapanDepartment of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanDepartment of Oceans Sciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Makoto M
authors.initials: MM
authors.lastname: Watanabe
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanResearch Program for Computational Science, Riken, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, JapanCenter for Interdisciplinary Research, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanFunabashi Shibayama High School, 7-39-1 Shibayama, Funabashi, Chiba 274-0816, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanNational Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-0053, JapanDepartment of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanDepartment of Oceans Sciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Tanaka
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanResearch Program for Computational Science, Riken, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, JapanCenter for Interdisciplinary Research, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanFunabashi Shibayama High School, 7-39-1 Shibayama, Funabashi, Chiba 274-0816, JapanResearch Center for Environmental Genomics, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe-shi, Hyogo 657-8501, JapanNational Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-0053, JapanDepartment of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, JapanDepartment of Oceans Sciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Nozaki
keywords: Chara braunii; adaptation; aquatic plant; diversifying selection; organelle DNA; speciation