title: A hypervariable mitochondrial protein coding sequence associated with geographical origin in a cosmopolitan bloom-forming alga,Heterosigma akashiwo.
abstract: Geographical distributions of phytoplankton species can be defined by events on both evolutionary time and shorter scales, e.g. recent climate changes. Additionally, modern industrial activity, including the transport of live fish and spat for aquaculture and aquatic microorganisms in ship ballast water, may aid the spread of phytoplankton. Obtaining a reliable marker is key to gaining insight into the phylogeographic history of a species. Here, we report a hypervariable mitochondrial gene in the cosmopolitan bloom-forming alga,Heterosigma akashiwoWe compared the entire mitochondrial genome sequences of sevenH. akashiwostrains from Japanese and North American coastal waters and identified a hypervariable segment. The region codes for a hypothetical protein with no defined function, and its variations between Japanese and North American isolates were prominent, while the sequences were more conserved among Japanese strains and North American isolates. Comparison of the sequence in isolates obtained from different geographical points in the Northern Hemisphere revealed that the sequence variations largely correlated with latitude and longitude (i.e. Pacific/Atlantic oceans). Our results demonstrate the usefulness of the sequence in determining the phylogeographic history ofH. akashiwo.
authors.affiliation: Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki, Okayama 710-0046, Japan.
authors.forename: Aiko
authors.initials: A
authors.lastname: Higashi
authors.affiliation: National Research Institute of Fisheries Science, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nagai
authors.affiliation: Department of Plant Biology and Ecology, University of the Basque Country, 48940 Leioa, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Seoane
authors.affiliation: Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki, Okayama 710-0046, Japan shokoueki@okayama-u.ac.jp.
authors.forename: Shoko
authors.identifier: 0000-0002-6558-652X
authors.initials: S
authors.lastname: Ueki
mesh_terms: D004141:Dinoflagellida / Q000235:genetics*; D005819:Genetic Markers / Q000235:genetics; D014644:Genetic Variation; D005843:Geography; D024101:Mitochondrial Proteins / Q000235:genetics*; D013045:Species Specificity
chemical_list: D005819:Genetic Markers; D024101:Mitochondrial Proteins
keywords: Heterosigma akashiwo; hypervariable regions; mitochondrial DNA; phytoplankton