Marine Biology

, Volume 156, Issue 5, pp 901–911

Geographical genetic structure and phylogeography of the Sargassum horneri/filicinum complex in Japan, based on the mitochondrial cox3 haplotype

  • Shinya Uwai
  • K. Kogame
  • G. Yoshida
  • H. Kawai
  • T. Ajisaka
Original Paper

DOI: 10.1007/s00227-009-1136-y

Cite this article as:
Uwai, S., Kogame, K., Yoshida, G. et al. Mar Biol (2009) 156: 901. doi:10.1007/s00227-009-1136-y

Abstract

The genetic structure and phylogeography of the brown seaweed Sargassum horneri/filicinum complex in Japan were studied based on the mitochondrial cox3 haplotype. The cox3 haplotypes found were divided into three clades in a statistical parsimony network, among which there were large numbers of steps. Contrary to the reported large amount of drifting S. horneri along the Japanese coast, the three clades were dividedly distributed on the Japanese coast: the northern Pacific, the central Pacific, and western Japan. The western Japan S. horneri had haplotypes that were phylogenetically closer to those of S. filicinum than to the northern and central Pacific S. horneri populations. The S. filicinum populations were included within the western Japan clade and grouped together with the S. horneri samples from western Japan. Taken together with the unstable morphological diagnosis, this result suggests that S. filicinum should be reduced into a synonymy of S. horneri. The TMRCA analysis suggested that the divergence time of each clade may go back to the last interglacial period and a skyline plot suggested that the last glacial maximum had only a small effect on the population size of S. horneri. The geographic subdivision of the three groups, in spite of a large amount of drifting mats, suggests a limited contribution of drifting mats to gene flow on a large geographic scale. On a small geographic scale, a small number of haplotypes were shared between S. horneri-type and S. filicinum-type populations. This result suggests that populations of these two types are partially, though not completely, isolated from each other, possibly by selfing in S. filicinum-type populations or by a difference in peak reproduction.

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Shinya Uwai
    • 1
    • 5
  • K. Kogame
    • 2
  • G. Yoshida
    • 3
  • H. Kawai
    • 1
  • T. Ajisaka
    • 4
  1. 1.Kobe University Research Center for Inland SeasKobeJapan
  2. 2.Department of Natural History Sciences, Faculty of ScienceHokkaido UniversitySapporoJapan
  3. 3.National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research AgencyHiroshimaJapan
  4. 4.Division of Applied Bioscience, Graduate School of AgricultureKyoto UniversityKyotoJapan
  5. 5.Department of Environmental Science, Faculty of ScienceNiigata UniversityNiigataJapan