Genetic structuring in the grooved carpet shell clam Ruditapes decussatus along the Moroccan coasts revealed by microsatellites

The geographical pattern of genetic diversity was investigated in the endemic Sicilian pond turtle Emys trinacris across its entire distribution range, using 16 microsatellite loci. Overall, 245 specimens of E. trinacris were studied, showing high polymorphic microsatellite loci, with allele numbers ranging from 7 to 30. STRUCTURE and GENELAND analyses showed a noteworthy, geographically based structuring of the studied populations in five well-characterized clusters, supported by a moderate degree of genetic diversity (FST values between 0.075 and 0.160). Possible explanations for the genetic fragmentation observed are provided, where both natural and human-mediated habitat fragmentation of the Sicilian wetlands played a major role in this process. Finally, some conservation and management suggestions aimed at preventing the loss of genetic variability of the species are briefly reported, stressing the importance of considering the five detected clusters as independent Management Units.

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Genome-wide SNPs redefines species boundaries and conservation units in the freshwater mussel genus Cyprogenia of North America

Scientific Reports ◽

10.1038/s41598-021-90325-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kyung Seok Kim ◽

Kevin J. Roe

Keyword(s):

Phylogenetic Analyses ◽

Freshwater Mussel ◽

Conservation Strategies ◽

Nucleotide Polymorphisms ◽

Conservation Units ◽

Genetic Structuring ◽

The North ◽

Snp Data ◽

Genome Wide ◽

Significant Difference

AbstractDetailed information on species delineation and population genetic structure is a prerequisite for designing effective restoration and conservation strategies for imperiled organisms. Phylogenomic and population genomic analyses based on genome-wide double digest restriction-site associated DNA sequencing (ddRAD-Seq) data has identified three allopatric lineages in the North American freshwater mussel genus Cyprogenia. Cyprogenia stegaria is restricted to the Eastern Highlands and displays little genetic structuring within this region. However, two allopatric lineages of C. aberti in the Ozark and Ouachita highlands exhibit substantial levels (mean uncorrected FST = 0.368) of genetic differentiation and each warrants recognition as a distinct evolutionary lineage. Lineages of Cyprogenia in the Ouachita and Ozark highlands are further subdivided reflecting structuring at the level of river systems. Species tree inference and species delimitation in a Bayesian framework using single nucleotide polymorphisms (SNP) data supported results from phylogenetic analyses, and supports three species of Cyprogenia over the currently recognized two species. A comparison of SNPs generated from both destructively and non-destructively collected samples revealed no significant difference in the SNP error rate, quality and amount of ddRAD sequence reads, indicating that nondestructive or trace samples can be effectively utilized to generate SNP data for organisms for which destructive sampling is not permitted.

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Toxicity assessment of organophosphorus in Ruditapes decussatus via physiological, chemical and biochemical determination: A case study with the compounds γ-oximo- and γ-amino-phosphonates and phosphine oxides

Marine Pollution Bulletin ◽

10.1016/j.marpolbul.2021.112556 ◽

2021 ◽

Vol 169 ◽

pp. 112556

Author(s):

Wiem Saidani ◽

Aymen Wahbi ◽

Badreddine Sellami ◽

Mohamed Amine Helali ◽

Abdelhafidh Khazri ◽

...

Keyword(s):

Toxicity Assessment ◽

Ruditapes Decussatus ◽

Phosphine Oxides ◽

Amino Phosphonates

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Larval cryopreservation as new management tool for threatened clam fisheries

Scientific Reports ◽

10.1038/s41598-021-94197-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

P. Heres ◽

J. Troncoso ◽

E. Paredes

Keyword(s):

Shell Growth ◽

Natural Populations ◽

Ruditapes Philippinarum ◽

Management Tool ◽

Equilibration Time ◽

Ruditapes Decussatus ◽

Larval Stages ◽

Long Term Storage ◽

Declining Species ◽

Conservation Of Endangered Species

AbstractCryopreservation is the only reliable method for long-term storage of biological material that guarantees genetic stability. This technique can be extremely useful for the conservation of endangered species and restock natural populations for declining species. Many factors have negatively affected the populations of high economical value shellfish in Spain and, as a result, many are declining or threatened nowadays. This study was focused on early-life stages of Venerupis corrugata, Ruditapes decussatus and Ruditapes philippinarum to develop successful protocols to enhance the conservation effort and sustainable shellfishery resources. Firstly, common cryoprotecting agents (CPAs) were tested to select the suitable permeable CPA attending to toxicity. Cryopreservation success using different combinations of CPA solutions, increasing equilibrium times and larval stages was evaluated attending to survival and shell growth at 2 days post-thawing. Older clam development stages were more tolerant to CPA toxicity, being ethylene-glycol (EG) and Propylene-glycol (PG) the least toxic CPAs. CPA solution containing EG yielded the highest post-thawing survival rate and the increase of equilibration time was not beneficial for clam larvae. Cryopreservation of trochophores yielded around 50% survivorship, whereas over 80% of cryopreserved D-larvae were able to recover after thawing.

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Genetic melting pot and importance of long-distance dispersal indicated in the Gladiolus imbricatus L. populations in the Polish Carpathians

Scientific Reports ◽

10.1038/s41598-021-96135-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Agnieszka Sutkowska ◽

Józef Mitka ◽

Tomasz Warzecha ◽

Jakub Bunk ◽

Julia Rutkowska ◽

...

Keyword(s):

Genetic Diversity ◽

Diversity Indices ◽

Western Carpathians ◽

Genetic Structuring ◽

Long Distance ◽

Plant Populations ◽

Genetic Stock ◽

Melting Pot ◽

Mountain Ranges ◽

Eastern Carpathians

AbstractThe genetic diversity in 11 populations of Gladiolus imbricatus in five mountain ranges, including the Tatra, Pieniny, Gorce, Beskid Niski (Western Carpathians) and Bieszczady Mts (Eastern Carpathians), was studied with inter-simple sequence repeat (ISSR) markers. The species is a perennial plant occurring in open and semi-open sites of anthropogenic origin (meadows and forest margins). We checked a hypothesis on the microrefugial character of the plant populations in the Pieniny Mts, a small calcareous Carpathian range of complicated relief that has never been glaciated. Plant populations in the Tatra and Pieniny Mts had the highest genetic diversity indices, pointing to their long-term persistence. The refugial vs. the non-refugial mountain ranges accounted for a relatively high value of total genetic variation [analysis of molecular variance (AMOVA), 14.12%, p = 0.003]. One of the Pieniny populations was of hybridogenous origin and shared genetic stock with the Tatra population, indicating there is a local genetic melting pot. A weak genetic structuring of populations among particular regions was found (AMOVA, 4.5%, p > 0.05). This could be an effect of the frequent short-distance and sporadic long-distance gene flow. The dispersal of diaspores between the remote populations in the Western Carpathians and Eastern Carpathians could be affected by the historical transportation of flocks of sheep from the Tatra to Bieszczady Mts.

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Genetic population structure of the monogenean parasite Gyrodactylus thymalli and its host European grayling (Thymallus thymallus) in a large Norwegian lake

Hydrobiologia ◽

10.1007/s10750-020-04431-7 ◽

2020 ◽

Author(s):

Ruben Alexander Pettersen ◽

Claudia Junge ◽

Kjartan Østbye ◽

Tor Atle Mo ◽

Leif Asbjørn Vøllestad

Keyword(s):

Genetic Structure ◽

Evolutionary Biology ◽

Isolation By Distance ◽

Genetic Structuring ◽

Thymallus Thymallus ◽

Homing Behavior ◽

Genetic Population ◽

Monogenean Parasite ◽

European Grayling ◽

Genetic Clusters

Abstract Understanding how populations are structured in space and time is a central question in evolutionary biology. Parasites and their hosts are assumed to evolve together, however, detailed understanding of mechanisms leading to genetic structuring of parasites and their hosts are lacking. As a parasite depends on its host, studying the genetic structure of both parasite and host can reveal important insights into these mechanisms. Here, genetic structure of the monogenean parasite Gyrodactylus thymalli and its host the European grayling (Thymallus thymallus) was investigated in 10 tributaries draining into the large Lake Mjøsa in Norway. The population genetic structure of spawning grayling was studied using microsatellite genotyping, while G. thymalli was studied by sequencing a mitochondrial DNA gene (dehydrogenase subunit 5). Two main genetic clusters were revealed in grayling, one cluster comprising grayling from the largest spawning population, while the remaining tributaries formed the second cluster. For both taxa, some genetic differentiation was observed among tributaries, but there was no clear isolation-by-distance signature. The structuring was stronger for the host than for the parasite. These results imply that moderate to high levels of gene flow occur among the sub-populations of both taxa. The high parasite exchange among tributaries could result from a lack of strong homing behavior in grayling as well as interactions among individual fish outside of the spawning season, leading to frequent mixing of both host and parasite.

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