DNA barcoding reveal patterns of species diversity among northwestern Pacific molluscs.

Shao’E Sun,Yanwei Feng,Hong Yu,Ruihai Yu,Lehai Ni,Xiaodong Zheng,Lina Dai,Lingfeng Kong,Jiping Lin,Zhenzhen Yu,Qi Li,Jun Chen,Jun Liu,Shanmei Zou,Yan Sun

doi:10.1038/srep33367

Shao’E Sun, Yanwei Feng + Show 13 more

Open Access

https://doi.org/10.1038/srep33367

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Journal: Scientific Reports	Publication Date: Sep 19, 2016
Citations: 30	License type: CC BY 4.0

Affiliation: Ocean University of China

Abstract

This study represents the first comprehensive molecular assessment of northwestern Pacific molluscs. In total, 2801 DNA barcodes belonging to 569 species from China, Japan and Korea were analyzed. An overlap between intra- and interspecific genetic distances was present in 71 species. We tested the efficacy of this library by simulating a sequence-based specimen identification scenario using Best Match (BM), Best Close Match (BCM) and All Species Barcode (ASB) criteria with three threshold values. BM approach returned 89.15% true identifications (95.27% when excluding singletons). The highest success rate of congruent identifications was obtained with BCM at 0.053 threshold. The analysis of our barcode library together with public data resulted in 582 Barcode Index Numbers (BINs), 72.2% of which was found to be concordantly with morphology-based identifications. The discrepancies were divided in two groups: sequences from different species clustered in a single BIN and conspecific sequences divided in one more BINs. In Neighbour-Joining phenogram, 2,320 (83.0%) queries fromed 355 (62.4%) species-specific barcode clusters allowing their successful identification. 33 species showed paraphyletic and haplotype sharing. 62 cases are represented by deeply diverged lineages. This study suggest an increased species diversity in this region, highlighting taxonomic revision and conservation strategy for the cryptic complexes.

Highlights

The region of the northwestern Pacific comprising the countries of China, Japan, North Korea, South Korea, and Russia is characterized by distinct tectonic and geographical features, producing more than 75 percent of the marginal basins found on the Earth today[10]
Surveys of three countries (Fig. 1) assemblages yielded a total of 2,801 sequences for the northwestern Pacific molluscs, belonging to 91 families, 240 genera, and 569 species
Multiple specimens were analyzed to document intraspecific variability. 182 species were represented by a single specimen, and 1 species (Cellana nigrolineata) was represented by 62 specimens

Summary

Introduction

The region of the northwestern Pacific comprising the countries of China, Japan, North Korea, South Korea, and Russia is characterized by distinct tectonic and geographical features, producing more than 75 percent of the marginal basins found on the Earth today[10]. The marine molluscs present a significant challenge for morphological approaches to specimen identification because they exhibit differences in life stage, frequently have morphologically cryptic taxa, and substantial phenotypic plasticity[15,16], which hampered the conservation and management of the richest diversity of this taxa. In this sense, reliable specimen identification and biodiversity monitoring of organism in the field is quite necessary. We establish a comprehensive barcode reference library for the marine molluscs of the northwestern Pacific (China, Japan and Korea), to test the efficacy of our DNA library for specimen identifications and shed new light on the northwestern Pacific molluscs diversity by employing different analytical approaches

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Conclusion