Genetic structure and diversity of Nodularia douglasiae (Bivalvia: Unionida) from the middle and lower Yangtze River drainage

PLOS ONE, Nov 2019

The Yangtze River drainage in China is among the most species rich rivers for freshwater mussels (order Unionida) on Earth with at least 68 species known. The freshwater mussels of the Yangtze River face a variety of threats with indications that species are declining in abundance and area of occupancy. This study represents the first analyses of the genetic structure and diversity for the common and widespread freshwater mussel Nodularia douglasiae based on microsatellite DNA genotypes and mitochondrial DNA sequences. Phylogenetic analysis a fragment of the COI mitochondrial gene indicated that N. douglasiae collected from across the middle and lower Yangtze River drainage are monophyletic with N. douglasiae from Japan, Russia, and South Korea. The results of the analysis of both the mtDNA and microsatellite datasets indicated that the seven collection locations of N. douglasiae in the middle and lower Yangtze River drainage showed high genetic diversity, significant genetic differentiation and genetic structure, and stable population dynamics over time. Moreover, we found that the connections among tributaries rivers and lakes in the Yangtze River drainage were important in maintaining gene flow among locations that N. douglasiae inhabits. An understanding of the genetic structure and diversity of a widespread species like N. douglasiae could be used as a surrogate to better understand the populations of other freshwater mussel species that are more rare in the Yangtze River drainage. At the same time, these results could provide a basis for the protection of genetic diversity and management of unionid mussels diversity and other aquatic organisms in the system.

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Genetic structure and diversity of Nodularia douglasiae (Bivalvia: Unionida) from the middle and lower Yangtze River drainage

December Genetic structure and diversity of Nodularia douglasiae (Bivalvia: Unionida) from the middle and lower Yangtze River drainage Xiongjun Liu 0 1 2 Yanling Cao 0 2 Taotao Xue 0 2 Ruiwen Wu 0 2 Yu Zhou 0 2 Chunhua Zhou 0 2 David T. Zanatta 0 2 Shan Ouyang 0 2 Xiaoping Wu 0 1 2 0 Central Michigan University Poyang Lake Research Investment Fund. Central Michigan University; the Key Laboratory of Poyang Lake Wetland and Watershed Research Director's Open Fund. Central Michigan University and Nanchang University; the National Nature Science Foundation of China (No. 31260515, No.81460318). Nanchang University , USA 1 Poyang Lake Key Laboratory of Environment and Resource Utilization (Nanchang University), Ministry of Education , Nanchang , People's Republic of China, 2 School of Resource, Environment and Chemical Engineering, Nanchang University , Nanchang , People's Republic of China, 3 School of Life Sciences, Nanchang University , Nanchang , People's Republic of China, 4 Central Michigan University, Institute for Great Lakes Research, Biology Department , Biosciences 2408, Mount Pleasant, MI , United States of America 2 Editor: John A. Craft, Glasgow Caledonian University , UNITED KINGDOM The Yangtze River drainage in China is among the most species rich rivers for freshwater mussels (order Unionida) on Earth with at least 68 species known. The freshwater mussels of the Yangtze River face a variety of threats with indications that species are declining in abundance and area of occupancy. This study represents the first analyses of the genetic structure and diversity for the common and widespread freshwater mussel Nodularia douglasiae based on microsatellite DNA genotypes and mitochondrial DNA sequences. Phylogenetic analysis a fragment of the COI mitochondrial gene indicated that N. douglasiae collected from across the middle and lower Yangtze River drainage are monophyletic with N. douglasiae from Japan, Russia, and South Korea. The results of the analysis of both the mtDNA and microsatellite datasets indicated that the seven collection locations of N. douglasiae in the middle and lower Yangtze River drainage showed high genetic diversity, significant genetic differentiation and genetic structure, and stable population dynamics over time. Moreover, we found that the connections among tributaries rivers and lakes in the Yangtze River drainage were important in maintaining gene flow among locations that N. douglasiae inhabits. An understanding of the genetic structure and diversity of a widespread species like N. douglasiae could be used as a surrogate to better understand the populations of other freshwater mussel species that are more rare in the Yangtze River drainage. At the same time, these results could provide a basis for the protection of genetic diversity and management of unionid mussels diversity and other aquatic organisms in the system. - Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Introduction Freshwater mussels (Bivalvia: Unionida) are one of the most important faunas in freshwater ecosystems, for their potential to enhance biodiversity and ecosystem functioning (e.g., the Leading Talent Training Plan of the GanPo Outstanding Talents 555 Project (No. 18000041). Nanchang University. This article is contribution 92 of the Central Michigan University Institute for Great Lakes Research. nutrient cycling and creating habitat for other benthic organisms)[1±4]. However, freshwater mussels are one of the most critically endangered faunal groups and are globally in decline [ 1,5 ]. Freshwater mussels also have an unusual life cycle, requiring a host fish species for larval (glochidia) development and dispersal[6]. This complex life cycle has the potential to drive genetic isolation between populations[ 7 ]. The obligate parasitic life stage may lead to phylogeographic patterns of conservation importance. The middle and lower reaches of the Yangtze River are a center for freshwater mussel diversity in East Asia with 68 described species[8±11]. However, in these regions, more than 80% of freshwater mussels are considered to be threatened or near threatened, and the dominant taxa of bivalves have shifted from large-sized unionids to the small-sized corbuculid clams (Cyrenidae)[12±13]. The decline of freshwater mussels diversity and abundance in the middle and lower reaches of the Yangtze River may be attributed to a variety of threats[8±10,12±14]: 1) fluctuations in water levels in river and lake levels coinciding with wet and dry seasons have become more extreme as a result of dam construction in the watershed and possibly due to human-induced climate change±these water level fluctutations may be very important in structuring habitat, and thus population and assemblage structure of unionid mussels; 2) the construction of large-scale impoundments and sand mining from the river benthos has resulted in destruction of habitats and h (...truncated)


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Xiongjun Liu, Yanling Cao, Taotao Xue, Ruiwen Wu, Yu Zhou, Chunhua Zhou, David T. Zanatta, Shan Ouyang, Xiaoping Wu. Genetic structure and diversity of Nodularia douglasiae (Bivalvia: Unionida) from the middle and lower Yangtze River drainage, PLOS ONE, 2017, Volume 12, Issue 12, DOI: 10.1371/journal.pone.0189737