Hidden diversity and phylogeographic history provide conservation insights for the edible seaweed Sargassum fusiforme in the Northwest Pacific

Understanding the evolutionary processes that have created diversity and the genetic potential of species to adapt to environmental change is an important premise for biodiversity conservation. Herein, we used mitochondrial trnW-L and cox3 and plastid rbcL-S data sets to analyze population genetic variation and phylogeographic history of the brown alga Sargassum fusiforme, whose natural resource has been largely exterminated in the Asia-Northwest Pacific in the past decades. Phylogenetic trees and network analysis consistently revealed three major haplotype-groups (A, B and C) in S. fusiforme, with A and B distributed in the Japan-Pacific coast. Group C consisted of three sub-groups (C1, C2 and C3) which were distributed in the Sea of Japan, the Yellow-Bohai Sea and East China Sea, respectively. Isolation-with-migration (IMa) analysis revealed that the three groups diverged approximately during the mid-Pleistocene (c. 756–1,224 ka). Extended Bayesian skyline plots (EBSP) showed that gro...