Comparative phylogeography in marginal seas of the northwestern Pacific

Abstract

The maturation of marine phylogeography depends on integration of comparative information across different regions globally. The northwestern Pacific, characterized by unique tectonic setting, however, is still underrepresented. This study seeks to highlight its phylogeographical history based on the available population data, focusing on three seas: the East China Sea (ECS), the South China Sea (SCS) and the Sea of Japan (SOJ). We first conducted a literature survey to evaluate current research efforts and then reanalysed the population structure, historical demography and genealogy for two selections of studies (namely 'the ECS category' and 'the multiple-sea category') to elucidate the evolutionary processes within and across the seas, respectively. For the ECS category, the meta-analyses revealed most studies displayed a shallow phylogeny, indicating a single origin from the sea. Significant population structure was commonplace, particularly in molluck and crustacean studies, with proportions of 89% and 80%, respectively. Nearly all studies selected showed signals of population expansion: the times estimated were closely linked to a period of~120-140 Kya rather than the last glacial maximum. For the latter category, divergent intraspecific lineages appeared among seas and overlapped in the adjacent regions, a pattern implying each sea had served as an independent refugium during glaciations. The genetic splits, however, were estimated to arise from separate events dating from late Miocene to middle Pleistocene. As phylogeography is still in its infancy in the region, more effort is needed to test and complement the general rules abstracted here. Finally, challenges and prospects were discussed to accelerate further research.

Genetic variation and population structure of the Pacific oyster Crassostrea gigas in the northwestern Pacific inferred from mitochondrial COI sequences

“…The weak differentiation was further revealed by the Bayesian phylogenetic tree and haplotypes networks. The major haplotype occurred in all sampling sites, demonstrating strong historical or current gene flow among all the populations at this spatial scale [16,20]. In addition, no evidence of IBD was found in this study.…”

“…Notably, most investigations with respect to population genetics and phylogeographic pattern of marine species have indicated that three marginal seas along the NW Pacific coast have served as independent refugiums during the low sea level periods of Pleistocene glaciations [20]. Therefore, marine organisms and their progenies might be divided into ECS, SCS, and JPS lineages after the rising of post-glacial sea levels.…”

“…Keywords Crassostrea gigas · Genetic structure · Mitochondrial DNA · Ocean current Biology differentiation [20]. Within interglacial periods, the sea level rose and quickly submerged the land bridges, leading to the reconnection of these marginal seas and the population-level expansion of species [21].…”

Seascape genetics of Indo-Pacific reef organisms: methodologies and case studies for an emerging discipline

“…5). A recent review of marine phylogeographic studies of this northwestern Pacific region suggests that most species have significant population structure (Ni et al 2014). Ni et al (2014) also suggested, that most of the included species had undergone a range expansion, based on network topology, neutrality statistics, and mismatch analyses.…”

“…A recent review of marine phylogeographic studies of this northwestern Pacific region suggests that most species have significant population structure (Ni et al 2014). Ni et al (2014) also suggested, that most of the included species had undergone a range expansion, based on network topology, neutrality statistics, and mismatch analyses. Our study extends these genetic diversity patterns; we find that the turnover component of β--diversity (βSIM) can also be high, and the richness component (βSNE) very low (indicative of restricted contemporary migration, Fig.…”