Connectivity Among Populations of the Top Shell Gibbula divaricata in the Adriatic Sea

Genetic connectivity studies are essential to understand species diversity and genetic structure and to assess the role of potential factors affecting connectivity, thus enabling sound management and conservation strategies. Here, we analyzed the patterns of genetic variability in the marine snail Gibbula divaricata from five coastal locations in the central-south Adriatic Sea (central Mediterranean) and one in the adjacent northern Ionian Sea, using 21 described polymorphic microsatellite loci. Observed and expected heterozygosity varied from 0.582 to 0.635 and 0.684 to 0.780, respectively. AMOVA analyses showed that 97% of genetic variation was observed within populations. Nevertheless, significant, although small, genetic differentiation was found among nearly all of the pairwise FST comparisons. Over a general pattern of panmixia, three groups of populations were identified: eastern Adriatic populations, western Adriatic populations, and a third group represented by the single northern Ionian Sea population. Nonetheless, migration and gene flow were significant between these groups. Gibbula divaricata is thought to have a limited dispersal capacity related to its lecithotrophic trochophore larval stage. Our results indicated high levels of self-recruitment and gene flow that is mainly driven through coastline dispersion, with populations separated by the lack of suitable habitats or deep waters. This stepping-stone mode of dispersion together with the high levels of self-recruitment could lead to higher levels of population structuring and differentiation along the Adriatic Sea. Large effective population sizes and episodic events of long-distance dispersal might be responsible for the weak differentiation observed in the analyzed populations. In summary, the circulation system operating in this region creates natural barriers for dispersion that, together with life-history traits and habitat requirements, certainly affect connectivity in G. divaricata. However, this scenario of potential differentiation seems to be overridden by sporadic events of long-distance dispersal across barriers and large effective population sizes

Connectivity Among Populations of the Top Shell Gibbula divaricata in the Adriatic Sea

Genetic connectivity studies are essential to understand species diversity and genetic structure and to assess the role of potential factors affecting connectivity, thus enabling sound management and conservation strategies. Here, we analyzed the patterns of genetic variability in the marine snail Gibbula divaricata from five coastal locations in the central-south Adriatic Sea (central Mediterranean) and one in the adjacent northern Ionian Sea, using 21 described polymorphic microsatellite loci. Observed and expected heterozygosity varied from 0.582 to 0.635 and 0.684 to 0.780, respectively. AMOVA analyses showed that 97% of genetic variation was observed within populations. Nevertheless, significant, although small, genetic differentiation was found among nearly all of the pairwise FST comparisons. Over a general pattern of panmixia, three groups of populations were identified: eastern Adriatic populations, western Adriatic populations, and a third group represented by the single northern Ionian Sea population. Nonetheless, migration and gene flow were significant between these groups. Gibbula divaricata is thought to have a limited dispersal capacity related to its lecithotrophic trochophore larval stage. Our results indicated high levels of self-recruitment and gene flow that is mainly driven through coastline dispersion, with populations separated by the lack of suitable habitats or deep waters. This stepping-stone mode of dispersion together with the high levels of self-recruitment could lead to higher levels of population structuring and differentiation along the Adriatic Sea. Large effective population sizes and episodic events of long-distance dispersal might be responsible for the weak differentiation observed in the analyzed populations. In summary, the circulation system operating in this region creates natural barriers for dispersion that, together with life-history traits and habitat requirements, certainly affect connectivity in G. divaricata. However, this scenario of potential differentiation seems to be overridden by sporadic events of long-distance dispersal across barriers and large effective population sizes

A population genomics insight by 2b‐RAD reveals populations' uniqueness along the Italian coastline in Leptopsammia pruvoti (Scleractinia, Dendrophylliidae)

Aim Marine bioconstructions such as coralligenous formations are hotspot of biodiversity and play a relevant ecological role in the preservation of biodiversity by providing carbon regulation, protection and nursery areas for several marine species. For this reason, the European Union Habitat Directive included them among priority habitats to be preserved. Although their ecological role is well established, connectivity patterns are still poorly investigated, representing a limit in conservation planning. The present study pioneers a novel approach for the analysis of connectivity in marine bioconstructor species, which often lack suitable genetic markers, by taking advantage of next‐generation sequencing techniques. We assess the geographical patterns of genomic variation of the sunset cup coral Leptopsammia pruvoti Lacaze‐Duthiers, 1897, an ahermatypic, non‐zooxanthellate and solitary scleractinian coral species common in coralligenous habitats and distributed across the Mediterranean Sea. Location The Italian coastline (Western and Central Mediterranean). Methods We applied the restriction site‐associated 2b‐RAD approach to genotype over 1,000 high‐quality and filtered single nucleotide polymorphisms in 10 population samples. Results The results revealed the existence of a strongly supported genetic structure, with highly significant pairwise FST values between all the population samples, including those collected about 5 km apart from each other. Moreover, genomic data indicate that the strongest barriers to gene flow are between the western (Ligurian–Tyrrhenian Sea) and the eastern side (Adriatic Sea) of the Italian peninsula. Main conclusions The strong differentiation found in L. pruvoti is similar to that found in other species of marine bioconstructors investigated in this area, but it strongly contrasts with the small differences found in many fish and invertebrates at the same geographical scale. All in one, our results highlight the importance of assessing connectivity in species belonging to coralligenous habitats as, due to their limited dispersal ability, they might require specific spatial conservation measures

Conservation genetics of Adriatic sturgeon (Acipenser naccarii)

The 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.Lo storione Cobice (Acipenser naccarii) è una specie endemica della regione Adriatica considerata a forte rischio di estinzione. La specie è caratterizzata da un genoma tetraploide e da un lungo ciclo vitale. Il recupero di questa specie dipende esclusivamente dalla gestione degli stock di prima generazione ottenuti da anni di riproduzioni a partire dall'unico stock di certa origine selvatica esistente. In questo studio è stata effettuata una completa caratterizzazione genetica di diversi stock F1 al fine di ricostruire i pedigree. Le informazioni ottenute sono state utilizzate per la pianificazione di una strategia coordinata volta alla gestione a lungo termine della specie mediante la costruzione di un piano di incroci specie-specifico. La strategia proposta è basata sulla pianificazione di incroci tra gruppi familiari definendo una priorità e dei criteri di scelta delle famiglie da incrociare. Questo lavoro rappresenta il primo piano gestionale per la specie A. naccarii e fornisce delle linee guida al fine di coordinare gli sforzi condotti da diversi allevamenti. L'approccio proposto rappresenta inoltre un esempio applicabile anche ad altre specie tetraploidi di storione

Conservation genetics of Adriatic sturgeon (Acipenser naccarii)

The 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.Lo storione Cobice (Acipenser naccarii) è una specie endemica della regione Adriatica considerata a forte rischio di estinzione. La specie è caratterizzata da un genoma tetraploide e da un lungo ciclo vitale. Il recupero di questa specie dipende esclusivamente dalla gestione degli stock di prima generazione ottenuti da anni di riproduzioni a partire dall'unico stock di certa origine selvatica esistente. In questo studio è stata effettuata una completa caratterizzazione genetica di diversi stock F1 al fine di ricostruire i pedigree. Le informazioni ottenute sono state utilizzate per la pianificazione di una strategia coordinata volta alla gestione a lungo termine della specie mediante la costruzione di un piano di incroci specie-specifico. La strategia proposta è basata sulla pianificazione di incroci tra gruppi familiari definendo una priorità e dei criteri di scelta delle famiglie da incrociare. Questo lavoro rappresenta il primo piano gestionale per la specie A. naccarii e fornisce delle linee guida al fine di coordinare gli sforzi condotti da diversi allevamenti. L'approccio proposto rappresenta inoltre un esempio applicabile anche ad altre specie tetraploidi di storione

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

The 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

Data from: "Transcriptomic resources for the critically endangered stellate sturgeon Acipenser stellatus" in Genomic Resources Notes accepted 1 April 2015 – 31 May 2015

This article documents the public availability of transcriptomic resources of the non-model and critically endangered starlet sturgeon Acipenser stellatus

make_repeated_assembly

Python script to perform iterative assemblies using MIRA 3.2 assemble

Captive Breeding Programs Based on Family Groups in Polyploid Sturgeons

In species with long life cycles and discontinuous availability of individuals to reproduction, implementing a long-term captive breeding program can be difficult or impossible. In such cases, managing diversity among familiar groups instead of individuals could become a suitable approach to avoid inbreeding and increase the possibility to accomplish a breeding scheme. This is the case of several sturgeon species including the Adriatic sturgeon, whose recovery depends on the management of a few captive stocks directly descended from the same group of wild parents. In the present study, relatedness among 445 potential breeders was inferred with a novel software for pedigree reconstruction in tetraploids ("BreedingSturgeons"). This information was used to plan a breeding scheme considering familiar groups as breeding units and identifying mating priorities. A two-step strategy is proposed: a short-term breeding program, relying on the 13 remaining F0 individuals of certain wild origin; and a long-term plan based on F1 families. Simulations to evaluate the loss of alleles in the F2 generation under different pairing strategies and assess the number of individuals to breed, costs and logistical aquaculture constraints were performed. The strategy proposed is transferable to the several other tetraploid sturgeon species on the brink of extinctio