scholarly journals How the truffle got its mate: insights from genetic structure in spontaneous and planted Mediterranean populations ofTuber melanosporum

2016 ◽  
Vol 25 (22) ◽  
pp. 5611-5627 ◽  
Author(s):  
E. Taschen ◽  
F. Rousset ◽  
M. Sauve ◽  
L. Benoit ◽  
M.-P. Dubois ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Mediterranean Populations

scholarly journals The Two Sides of the Mediterranean: Population Genomics of the Black Sea Urchin Arbacia lixula (Linnaeus, 1758) in a Warming Sea

2021 ◽  
Vol 8 ◽  
Author(s):  
Carlos Carreras ◽  
Víctor Ordóñez ◽  
Àlex García-Cisneros ◽  
Owen S. Wangensteen ◽  
Creu Palacín ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Genetic Differentiation ◽  
Sea Urchin ◽  
Black Sea ◽  
Population Genomics ◽  
Environmental Data ◽  
The Black Sea ◽  
Mediterranean Populations ◽  
The Mediterranean ◽  
Arbacia Lixula

Global environmental changes may have a profound impact on ecosystems. In this context, it is crucial to gather biological and ecological information of the main species in marine communities to predict and mitigate potential effects of shifts in their distribution, abundance, and interactions. Using genotyping by sequencing (GBS), we assessed the genetic structure of a keystone species in the Mediterranean shallow littoral ecosystems, the black sea urchin Arbacia lixula. This bioengineer species can shape their communities due to its grazing activity and it is experiencing an ongoing expansion with increasing temperatures. The population genomic analyses on 5,241 loci sequenced in 240 individuals from 11 Mediterranean sampled populations revealed that all populations were diverse and showed significant departure from equilibrium. Albeit genetic differentiation was in general shallow, a significant break separated the western and eastern Mediterranean populations, a break not detected in previous studies with less resolutive markers. Notably, no clear effect of the Almería-Oran front, an important break in the Atlanto-Mediterranean transition, could be detected among the western basin populations, where only a slight differentiation of the two northernmost populations was found. Despite the generally low levels of genetic differentiation found, we identified candidate regions for local adaptation by combining different genomic analysis with environmental data. Salinity, rather than temperature, seemed to be an important driver of genetic structure in A. lixula. Overall, from a population genomics standpoint, there is ample scope for A. lixula to continue thriving and adapting in the warming Mediterranean.

scholarly journals A tale of two seas: contrasting patterns of population structure in the small-spotted catshark across Europe

2014 ◽  
Vol 1 (3) ◽  
pp. 140175 ◽  
Author(s):  
Chrysoula Gubili ◽  
David W. Sims ◽  
Ana Veríssimo ◽  
Paolo Domenici ◽  
Jim Ellis ◽  
...  
Keyword(s):  
Population Structure ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Spatial Scales ◽  
Sea Level Changes ◽  
Glacial Cycles ◽  
Mediterranean Populations ◽  
Population Reduction ◽  
The Mediterranean

Elasmobranchs represent important components of marine ecosystems, but they can be vulnerable to overexploitation. This has driven investigations into the population genetic structure of large-bodied pelagic sharks, but relatively little is known of population structure in smaller demersal taxa, which are perhaps more representative of the biodiversity of the group. This study explores spatial population genetic structure of the small-spotted catshark ( Scyliorhinus canicula ), across European seas. The results show significant genetic differences among most of the Mediterranean sample collections, but no significant structure among Atlantic shelf areas. The data suggest the Mediterranean populations are likely to have persisted in a stable and structured environment during Pleistocene sea-level changes. Conversely, the Northeast Atlantic populations would have experienced major changes in habitat availability during glacial cycles, driving patterns of population reduction and expansion. The data also provide evidence of male-biased dispersal and female philopatry over large spatial scales, implying complex sex-determined differences in the behaviour of elasmobranchs. On the basis of this evidence, we suggest that patterns of connectivity are determined by trends of past habitat stability that provides opportunity for local adaptation in species exhibiting philopatric behaviour, implying that resilience of populations to fisheries and other stressors may differ across the range of species.

Phylogeny and genetic structure of Tunisians and their position within Mediterranean populations

2014 ◽  
Vol 26 (4) ◽  
pp. 593-604 ◽  
Author(s):  
Rym Kefi ◽  
Sana Hsouna ◽  
Nizar Ben Halim ◽  
Khaled Lasram ◽  
Lilia Romdhane ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Mediterranean Populations

scholarly journals Genetic homogeneity, lack of larvae recruitment, and clonality in absence of females across western Mediterranean populations of the starfish Coscinasterias tenuispina

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rocío Pérez-Portela ◽  
Alex Garcia-Cisneros ◽  
Marta Campos-Canet ◽  
Creu Palacín
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Asexual Reproduction ◽  
Genetic Variants ◽  
Western Mediterranean ◽  
Genetic Homogeneity ◽  
Relative Importance ◽  
Mediterranean Populations ◽  
Time Points ◽  
Over Time

Abstract We here analysed the populations’ genetic structure of Coscinasterias tenuispina, an Atlantic-Mediterranean fissiparous starfish, focusing on the western Mediterranean, to investigate: the distribution and prevalence of genetic variants, the relative importance of asexual reproduction, connectivity across the Atlantic-Mediterranean transition, and the potential recent colonisation of the Mediterranean Sea. Individuals from 11 Atlantic-Mediterranean populations of a previous study added to 172 new samples from five new W Mediterranean sites. Individuals were genotyped at 12 microsatellite loci and their gonads histologically analysed for sex determination. Additionally, four populations were genotyped at two-time points. Results demonstrated genetic homogeneity and low clonal richness within the W Mediterranean, due to the dominance of a superclone, but large genetic divergence with adjacent areas. The lack of new genotypes recruitment over time, and the absence of females, confirmed that W Mediterranean populations were exclusively maintained by fission and reinforced the idea of its recent colonization. The existence of different environmental conditions among basins and/or density-depend processes could explain this lack of recruitment from distant areas. The positive correlation between clonal richness and heterozygote excess suggests that most genetic diversity is retained within individuals in the form of heterozygosity in clonal populations, which might increase their resilience.

scholarly journals Concordant patterns of mtDNA and nuclear phylogeographic structure reveal Pleistocene vicariant event in the green crab Carcinus aestuarii across the Siculo-Tunisian Strait

2016 ◽  
Vol 17 (2) ◽  
pp. 533 ◽  
Author(s):  
T. DELI ◽  
N. CHATTI ◽  
K. SAID ◽  
C. D SCHUBART
Keyword(s):  
Genetic Structure ◽  
Demographic History ◽  
Time Estimation ◽  
Mediterranean Coast ◽  
Green Crab ◽  
Early Pleistocene ◽  
Phylogeographic Structure ◽  
Secondary Contact ◽  
Mediterranean Populations ◽  
Vicariant Event

This study focuses on the population genetic structure of the green crab Carcinus aestuarii along part of the African Mediterranean coast, with the main target to confirm genetic subdivision across the well documented genetic boundary of the Siculo-Tunisian Strait. For this purpose, the mitochondrial COI (cytochrome oxidase I) gene and five polymorphic microsatellite loci were analysed in 144 and 120 specimens, respectively. Our results show the existence of two distinct haplogroups, separated by 16 mutational steps and revealed a non random distribution of the genetic variation along the African Mediterranean coast. Dating analyses, based on the use of different molecular clock models and rates, placed the divergence among both haplogroups at 1.91 Myr (95% HPD: 1.11–2.68 Myr) to 0.69 Myr (95% HPD: 0.44–0.98 Myr). This range of divergence time estimation corresponds to the Early Pleistocene. The particular pattern of genetic divergence among Eastern and Western African Mediterranean populations of C. aestuarii, detected by 2-level AMOVA at the mitochondrial level, was consistent with that inferred from microsatellite analysis and suggests a vicariant event in C. aestuarii. Demographic reconstruction, inferred from mismatch distribution and BSP analyses, yielded different patterns of demographic history between both African Mediterranean groups. The distribution pattern of the two haplogroups across the African Mediterranean coast, along with results of Bayesian analysis of genetic structure revealing an intermediate geographic group between the two divergent groups of the African coast, support the hypothesis of a secondary contact between two historically isolated groups. Although this hypothetical contact zone, thought to be located near the Siculo-Tunisian Strait, still needs to be verified, the asymmetric gene flow from Western to Eastern African Mediterranean, as inferred by the results of a MIGRATE analysis, reinforces the previously mentioned results.

scholarly journals Population structure and geographically structured reproductive strategies of the haplodiplontic seaweed Dictyota dichotoma

2019 ◽  
Author(s):  
Frédérique Steen ◽  
Verlaque Marc ◽  
Sofie D’hondt ◽  
Christophe Vieira ◽  
Olivier De Clerck
Keyword(s):  
South Africa ◽  
Genetic Structure ◽  
Sexual Reproduction ◽  
Canary Islands ◽  
Isolation By Distance ◽  
Glacial Refugia ◽  
Population Diversity ◽  
Mediterranean Populations ◽  
Dictyota Dichotoma ◽  
Southern Norway

AbstractBoth mating system variation and the propensity of many seaweeds to reproduce both sexually and asexually, leave a strong imprint in the genetic structure of species. In this respect, we study the population genetic structure of Dictyota dichotoma, a common haplodiplont brown subtidal seaweed. This benthic species is widespread in the NE-Atlantic, from the Canary Islands and Mediterranean Sea to southern Norway, but lately populations have been reported from Argentina and South Africa. Phenology and reproduction of D. dichotoma was monitored year-round in four populations to investigate how the species has adapted to the steep thermal gradient in southern and northern ranges of its distribution. Thirteen microsatellites are developed in order to assess patterns of population diversity and structure across the biogeographic range, as shaped by past and present processes. Last, we assess the genetic structure of South African and South American populations and their relationship to the northern hemisphere populations.Throughout its range, D. dichotoma shows a varying reproductive effort, with sexual reproduction being more abundant in the northern range. In contrast, the Mediterranean populations show a clear sporophyte dominance, suggesting that sexual reproduction is not the prime mode of reproduction, and indicating that the species potentially resorts to other modes of propagation as for instance fragmentation or apospory.Genetic diversity is highest in the southern population decreasing gradually northward, indicative for a recolonization pattern after the demise of the last glacial maximum where these areas served as glacial refugia. European mainland populations show an isolation by distance pattern, while the population in the Canary Islands has its own genetic identity, being significantly diverged from the mainland population. Populations in South Africa and Argentina are seemingly introduced from mainland Europe, but no conclusion can be made on the exact timing of these introductions.

scholarly journals Allozymic variation in Northeast Atlantic and Mediterranean populations of Norway lobster, Nephrops norvegicus

2006 ◽  
Vol 63 (5) ◽  
pp. 875-882 ◽  
Author(s):  
Costas Stamatis ◽  
Alexander Triantafyllidis ◽  
Katerina A. Moutou ◽  
Zissis Mamuris
Keyword(s):  
Genetic Structure ◽  
Aegean Sea ◽  
Mediterranean Population ◽  
Starch Gel Electrophoresis ◽  
Nephrops Norvegicus ◽  
Genetic Studies ◽  
Mediterranean Populations ◽  
The North ◽  
Enzymatic Systems ◽  
Starch Gel

Abstract Allozyme starch gel electrophoresis was used to investigate the genetic structure of Nephrops norvegicus populations in an extended sampling scheme. Nine populations from the North Sea and Aegean Sea were sampled and analysed using ten enzymatic systems corresponding to 15 putative loci. Values of heterozygosity were similar between Atlantic and Mediterranean population samples, ranging from 0.165 to 0.187. Genetic distance estimates, FST analyses and tests for genetic differentiation revealed a heterogeneous genetic structure within the sampling area of N. norvegicus. No evidence was found of past separation of Atlantic and Mediterranean populations, agreeing with the results of previous allozymic and mitochondrial genetic studies of N. norvegicus. Data are compared with genetic studies of other marine crustaceans and fish, and the implications for management of N. norvegicus stocks are discussed.

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