1,721,001 research outputs found
The need for genetic support in restocking activities andex situconservation programmes: the case of the Adriatic sturgeon (Acipenser naccariiBonaparte, 1836) in the Ticino River Park
No full textThe Adriatic sturgeon (Acipenser naccarii Bonaparte, 1836), endemic to the North Adriatic region, was recently reclassified by IUCN as 'Critically endangered and possibly extinct in the wild' since no natural spawning has been recorded in the last 20 years. Its survival relies on restocking activities originating from a single captive broodstock collected by a private aquaculture plant (V.I.P.) in the 1970s and is currently reduced to 13 individuals. Few alternative brood-stocks of F1 animals have been retained for use in the near future. Thus far, brood-stocks, as well as all stocks released in the wild, have been randomly chosen without regard to their genetic composition. The consequence of breeding programmes with no genetic input was evaluated in the Ticino River Park (TRP) in Italy. A parental allocation procedure based on microsatellite markers useful for tetraploids was used following a Band-Sharing approach. Levels of relatedness within the TRP F1 captive breeders (Stock_1) and among animals released by TRP in the past (Stock_2) were explored and compared with the stock of wild origin. The pronounced decrease in genetic diversity observed in the analysed sample suggests the need for complete reorganization and coordination of conservation efforts for this species, paying particular attention to the long-term preservation of the genetic diversity. Also identified is the only potentially suitable stock of F1 animals that should be used as source of future breeders
Conservation genetics of Adriatic sturgeon (Acipenser naccarii)
Full text linkThe Adriatic sturgeon (Acipenser naccarii) is a critically endangered endemism of the Adriatic region, with tetraploid genome and long life cycle. Its recovery totally depends on the management of few F1 captive stocks that have now reached the sexual maturity and directly descend from the last group of wild animals.
In the present study, an exhaustive genetic characterization was performed in order to reconstruct individual pedigrees. This information was used to plan a coordinated strategy for successful long-term species preservation through the designing of a breeding plan in which the different familiar groups are considered as breeding units, and in which the mating priorities are identified.
This work represents the first breeding plan for the Adriatic sturgeon and provides common guidelines for the coordination of the unlinked and too often short-term efforts made by different local administrations. The approach here proposed can be also transferred to the several other tetraploid sturgeon species on the brink of extinction
Inheritance pattern of microsatellite loci in the polyploid Adriatic sturgeon (Acipenser naccarii)
No full textThe Adriatic sturgeon is a highly endangered tetraploid species whose conservation depends up ex-situ management of the remnant genetic variability. Understanding whether the species follows a tetrasomic or a disomic inheritance pattern is of primary importance to set up a parental allocation procedure and to establish a long-term breeding plan. Moreover, comprehending the inheritance modality can strongly contribute to understanding the origin of tetraploidy in this species. For this purpose, microsatellite inheritance patterns were analyzed in 7 complete families and at 7 loci for a total of 12 family/locus combinations. For each available family, a preliminary selection of loci was performed, in order to avoid ambiguities due to allele dosage, null alleles or interference between parental contributions. Results allowed to unambiguously reject a strict disomic inheritance pattern and to suggest tetrasomy as the more likely model. Accordingly, parental chromosomes can be expected to pair in the gametes in all possible combinations, though a certain degree of preferential pairing could not be excluded for the limited statistical power reached. This study represents the first investigation of the inheritance pattern in the Adriatic sturgeon and provides relevant information for the correct management of its residual genetic diversity. Published by Elsevie
Species and hybrid identification of sturgeon caviar: a new molecular approach to detect illegal trade
No full textOverexploitation of wild populations due to the high economic value of caviar has driven sturgeons to near extinction. The high prices commanded by caviar on world markets have made it a magnet for illegal and fraudulent caviar trade, often involving low-value farmed caviar being sold as top-quality caviar. We present a new molecular approach for the identification of pure sturgeon species and hybrids that are among the most commercialized species in Europe and North America. Our test is based on the discovery of species-specific single nucleotide polymorphisms (SNPs) in the ribosomal protein S7, supplemented with the Vimentin gene and the mitochondrial D-loop. Test validations performed in 702 specimens of target and nontarget sturgeon species demonstrated a 100% identification success for Acipenser naccarii, A. fulvescens, A. stellatus, A. sinensis and A. transmontanus. In addition to species identification, our approach allows the identification of Bester and AL hybrids, two of the most economically important hybrids in the world, with 80% and 100% success, respectively. Moreover, the approach has the potential to identify many other existing sturgeon hybrids. The development of a standardized sturgeon identification tool will directly benefit trade law enforcement, providing the tools to monitor and regulate the legal trade of caviar and protect sturgeon stocks from illicit producers and traders, hence contributing to safeguarding this group of heavily threatened species
A new marker, isolated by ddRAD sequencing, detects Siberian and Russian sturgeon in hybrids
No full textMicrosatellites from the genome and the transcriptome of the tetraploid Adriatic sturgeon, Acipenser naccarii (Bonaparte, 1836) and cross-species applicability to the diploid beluga sturgeon, Huso huso (Linnaeus, 1758)
No full textNinety-five microsatellite loci were isolated from the output of two Next Generation Sequencing projects: a genomic Illumina RADSeq and a transcriptomic Roche 454 cDNA sequencing of the Adriatic sturgeon (Acipenser naccarii). From a total of 7697 loci identified, 72 were characterized and 57 were polymorphic in the tetraploid A. naccarii, providing new markers suitable for parental allocations to be performed for future conservation actions. Loci isolated from the transcriptome showed a higher level of polymorphism, which could be related to the different sequencing approaches used. Notably, a higher rate of duplication was observed in the transcribed loci, pointing to a preferential retention of sequences with a functional role after whole genome duplications occurred in sturgeons. Cross-species amplification of these markers was also assessed in the diploid beluga sturgeon (Huso huso), with the aim of setting up a panel of markers to be applied in future conservation programmes regarding this species
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
WILD MEAT and DERIVED PRODUCTS: identification, characterisation, labelling
Full text linkopenPer frode alimentare si intende la produzione ed il commercio di alimenti non conformi alle normative vigenti. Nelle carni e nei prodotti da essi derivati, il 29% dei casi di frodi alimentari è imputabile a sostituzione di specie, in cui le carni di specie pregiate, vengono sostituite con quelle di specie meno pregiate pertanto l’identificazione di specie negli alimenti di origine animale è importante per difendere la tutela dei consumatori. Lo scopo di questa tesi è quello di identificare le specie di selvaggina in carni fresche e in alimenti tipici regionali del Sud Tirolo, verificando quanto dichiarato nelle etichette dei vari prodotti presenti in commercio. Il metodo utilizzato in questo lavoro per identificare le specie, è il DNA Barcoding che si basa sull’amplificazione e sul sequenziamento di un frammento del gene mitocondriale codificante per la subunità I della Citocromo Ossidasi I (COI). La sua applicazione, permette di verificare la corretta etichettatura dei prodotti venduti ai consumatori con un’alta affidabilità, anche quando il prodotto ha subito un' importante trasformazione.Food fraud refers to the production and trade of food that does not comply with current regulations. In meat and meat products, 29% of cases of food fraud are caused by species substitution, in which the meat of valuable species, are replaced by less valuable species, therefore the identification of species in food of animal origin is important to defend consumer protection. The aim of this thesis is to identify the species of game in fresh meat and typical regional food of South Tyrol, verifying what is stated in the labels of the various products on the market. The method used in this work to identify species is DNA Barcoding, which is based on the amplification and sequencing of a fragment of the mitochondrial gene coding for subunit I of Cytochrome Oxidase I (COI). Its application makes it possible to verify the correct labelling of products sold to consumers with high reliability, even when the product has undergone an important transformation
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
