Phylogeographic heterogeneity of the brown macroalga Sargassum horneri (Fucaceae) in the northwestern Pacific in relation to late Pleistocene glaciation and tectonic configurations

Pleistocene glacial oscillations and associated tectonic processes are believed to have influenced the historical abundances and gradients of organisms in the Asia Northwest Pacific (ANP) Ocean. However, accumulating evidence indicates that factors shaping tempo-spatial population dynamics and distribution patterns of marine taxa vary with biogeographical latitude, pelagic behavior and oceanographic regimes. To detect what kinds of historical and contemporary factors affected genetic connectivity, phylogeographic profiles of littoral macroalga Sargassum horneri in the ANP were analyzed based on mitochondrial (Cox3) and chloroplast (rbcL) data sets. Five distinct clades were recovered. A strong signature of biogeographical structure was revealed (ФCT = 0.487, P < 0.0001) derived from remarkable differentiation in clade distribution, as clade I is highly harboured along Chinese marginal seas (Yellow-Bohai Sea, East China Sea and South China Sea), whereas clades II-V are discontinuously...