A hypervariable mitochondrial protein coding sequence associated with geographical origin in a cosmopolitan bloom-forming alga, Heterosigma akashiwo

Aiko Higashi, Satoshi Nagai, Sergio Seone, Shoko Ueki

Research output: Contribution to journalArticle

3 Citations (Scopus)


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 bloomforming alga, Heterosigma akashiwo. We compared the entire mitochondrial genome sequences of seven H. akashiwo strains 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 of H. akashiwo.

Original languageEnglish
Article number0976
JournalBiology Letters
Issue number4
Publication statusPublished - Apr 1 2017



  • Heterosigma akashiwo
  • Hypervariable regions
  • Mitochondrial DNA
  • Phytoplankton

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Agricultural and Biological Sciences(all)

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