scholarly journals Hierarchical genetic structuring in the cool boreal kelp, Laminaria digitata: implications for conservation and management

2020 ◽  
Vol 77 (5) ◽  
pp. 1906-1913 ◽  
Author(s):  
Nathan G King ◽  
Niall J McKeown ◽  
Dan A Smale ◽  
Sunny Bradbury ◽  
Thomas Stamp ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Spatial Scales ◽  
Glacial Refugia ◽  
Laminaria Digitata ◽  
Genetic Structuring ◽  
Neutral Genetic Diversity ◽  
Poor Indicator ◽  
Glacial Refuge ◽  
Northeastern Atlantic Ocean ◽  
Northeastern Atlantic

Abstract Kelp are foundation species threatened by ongoing warming trends and increased harvesting pressure. This emphasizes the need to study genetic structure over various spatial scales to resolve demographic and genetic processes underpinning resilience. Here, we investigate the genetic diversity in the kelp, Laminaria digitata, in previously understudied southern (trailing-edge) and northern (range-centre) regions in the Northeastern Atlantic Ocean. There was strong hierarchical spatial structuring with significantly lower genetic variability and gene flow among southern populations. As these span the area of the Hurd’s deep Pleistocene glacial refuge, the current low variation likely reflects a fraction of previous levels that has been eroded at the species southern edge. Northern variability and private alleles also indicate contributions from cryptic northern glacial refugia. Contrary to expectations of a positive relationship between neutral genetic diversity and resilience, a previous study reported individuals from the same genetically impoverished southern populations to be better adapted to cope with thermal stress than northern individuals. This not only demonstrates that neutral genetic diversity may be a poor indicator of resilience to environmental stress but also confirms that extirpation of southern populations will result in the loss of evolved, not just potential, adaptations for resilience.

scholarly journals Genetic variation in Irish Sea brown crab (Cancer pagurus L.): implications for local and regional management

2018 ◽  
Vol 99 (4) ◽  
pp. 879-886 ◽  
Author(s):  
Niall J. McKeown ◽  
Hayley V. Watson ◽  
Ilaria Coscia ◽  
Emma Wootton ◽  
Joseph E. Ironside
Keyword(s):  
Genetic Diversity ◽  
Spatial Scales ◽  
Management Strategies ◽  
Irish Sea ◽  
Cancer Pagurus ◽  
Neutral Genetic Diversity ◽  
Demographic Processes ◽  
High Gene ◽  
The Irish Sea ◽  
Genetic Patchiness

AbstractUnderstanding demographic processes over multiple spatial scales is vital for the optimization of conservation/management strategies, particularly for commercially harvested taxa such as the brown crab (Cancer pagurus L). Brown crab population genetic structure was investigated at (i) a local scale within the Irish Sea, which included comparisons with the Lundy No Take Zone (NTZ) and (ii) across the NE Atlantic. The results indicate that the brown crab does not exhibit strong spatial structure either within the Irish Sea or at the regional level, suggesting high gene flow within and among the Irish Sea, English Channel and North Sea. Comparisons between the Lundy NTZ and harvested areas revealed similarly high levels of genetic diversity. An intriguing result was that the Lundy NTZ sample exhibited a degree of genetic patchiness (ephemeral geographically unpatterned differentiation) which may indicate elevated recruitment skews within the NTZ. Overall, the results support the view that brown crabs within the sampled area belong to a single genetically panmictic stock and that if breeding stock sizes are maintained genetic drift will not be strong enough to reduce neutral genetic diversity. The highly connected nature of this species requires international cooperation for sustainable management, an important component of which will be the application of more powerful population genomic approaches to assess finer scale aspects of stock structure as well drivers of genetic patchiness reported for the species. This is a timely consideration in light of potential future misalignments between biological and geopolitical stock boundaries in the Irish Sea following Brexit.

Protected areas of Spain preserve the neutral genetic diversity of Quercus ilex L. irrespective of glacial refugia

2015 ◽  
Vol 11 (6) ◽  
Author(s):  
Beatriz Guzmán ◽  
Carlos M. Rodríguez López ◽  
Alan Forrest ◽  
Emilio Cano ◽  
Pablo Vargas
Keyword(s):  
Genetic Diversity ◽  
Protected Areas ◽  
Quercus Ilex ◽  
Glacial Refugia ◽  
Neutral Genetic Diversity

scholarly journals The Patterns and Puzzles of Genetic Diversity of Endangered Freshwater Mussel Unio crassus Philipsson, 1788 Populations from Vistula and Neman Drainages (Eastern Central Europe)

Life ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 119
Author(s):  
Adrianna Kilikowska ◽  
Monika Mioduchowska ◽  
Anna Wysocka ◽  
Agnieszka Kaczmarczyk-Ziemba ◽  
Joanna Rychlińska ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Spatial Scales ◽  
Freshwater Mussel ◽  
Its Region ◽  
Strong Relationship ◽  
Mantel Test ◽  
Freshwater Ecosystems ◽  
Hierarchical Organization ◽  
Anthropogenic Factors

Mussels of the family Unionidae are important components of freshwater ecosystems. Alarmingly, the International Union for Conservation of Nature and Natural Resources Red List of Threatened Species identifies almost 200 unionid species as extinct, endangered, or threatened. Their decline is the result of human impact on freshwater habitats, and the decrease of host fish populations. The Thick Shelled River Mussel Unio crassus Philipsson, 1788 is one of the examples that has been reported to show a dramatic decline of populations. Hierarchical organization of riverine systems is supposed to reflect the genetic structure of populations inhabiting them. The main goal of this study was an assessment of the U. crassus genetic diversity in river ecosystems using hierarchical analysis. Different molecular markers, the nuclear ribosomal internal transcribed spacer ITS region, and mitochondrial DNA genes (cox1 and ndh1), were used to examine the distribution of U. crassus among-population genetic variation at multiple spatial scales (within rivers, among rivers within drainages, and between drainages of the Neman and Vistula rivers). We found high genetic structure between both drainages suggesting that in the case of the analyzed U. crassus populations we were dealing with at least two different genetic units. Only about 4% of the mtDNA variation was due to differences among populations within drainages. However, comparison of population differentiation within drainages for mtDNA also showed some genetic structure among populations within the Vistula drainage. Only one haplotype was shared among all Polish populations whereas the remainder were unique for each population despite the hydrological connection. Interestingly, some haplotypes were present in both drainages. In the case of U. crassus populations under study, the Mantel test revealed a relatively strong relationship between genetic and geographical distances. However, in detail, the pattern of genetic diversity seems to be much more complicated. Therefore, we suggest that the observed pattern of U. crassus genetic diversity distribution is shaped by both historical and current factors i.e. different routes of post glacial colonization and history of drainage systems, historical gene flow, and more recent habitat fragmentation due to anthropogenic factors.

scholarly journals Stand out from the Crowd: Small-Scale Genetic Structuring in the Endemic Sicilian Pond Turtle

Diversity ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 343
Author(s):  
Luca Vecchioni ◽  
Federico Marrone ◽  
Marco Arculeo ◽  
Uwe Fritz ◽  
Melita Vamberger
Keyword(s):  
Genetic Diversity ◽  
Microsatellite Loci ◽  
Small Scale ◽  
Moderate Degree ◽  
Geographical Pattern ◽  
Genetic Structuring ◽  
Pond Turtle ◽  
Emys Trinacris ◽  
Polymorphic Microsatellite ◽  
Entire Distribution

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.

Is neutral genetic diversity related to quantitative variation in semen traits in bulls?

2021 ◽  
Author(s):  
Eddington Gororo ◽  
Fungayi Primrose Chatiza ◽  
Farisai Chidzwondo ◽  
Stanley Marshall Makuza
Keyword(s):  
Genetic Diversity ◽  
Quantitative Variation ◽  
Neutral Genetic Diversity

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

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.

scholarly journals Fine-Scale Population Genetic Structure and Within-Tree Distribution of Mating Types of Venturia effusa, Cause of Pecan Scab in the United States

2018 ◽  
Vol 108 (11) ◽  
pp. 1326-1336 ◽  
Author(s):  
Clive H. Bock ◽  
Carolyn A. Young ◽  
Katherine L. Stevenson ◽  
Nikki D. Charlton
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Asexual Reproduction ◽  
Population Genetic ◽  
Spatial Scales ◽  
The United States ◽  
Source Population ◽  
Mating Types ◽  
Fine Scale ◽  
Scale Population

Scab (caused by Venturia effusa) is the major disease of pecan in the southeastern United States. There is no information available on the fine-scale population genetic diversity or the occurrence of clonal types at small spatial scales that provides insight into inoculum sources and dispersal mechanisms, and potential opportunity for sexual reproduction. To investigate fine-scale genetic diversity, four trees of cultivar Wichita (populations) were sampled hierarchically: within each tree canopy, four approximately evenly spaced terminals (subpopulations) were selected and up to six leaflets (sub-subpopulations) were sampled from different compound leaves on each terminal. All lesions (n = 1 to 8) on each leaflet were sampled. The isolates were screened against a panel of 29 informative microsatellite markers and the resulting multilocus genotypes (MLG) subject to analysis. Mating type was also determined for each isolate. Of 335 isolates, there were 165 MLG (clonal fraction 49.3%). Nei’s unbiased measure of genetic diversity for the clone-corrected data were moderate to high (0.507). An analysis of molecular variance demonstrated differentiation (P = 0.001) between populations on leaflets within individual terminals and between terminals within trees in the tree canopies, with 93.8% of variance explained among isolates within leaflet populations. Other analyses (minimum-spanning network, Bayesian, and discriminant analysis of principal components) all indicated little affinity of isolate for source population. Of the 335 isolates, most unique MLG were found at the stratum of the individual leaflets (n = 242), with similar total numbers of unique MLG observed at the strata of the terminal (n = 170), tree (n = 166), and orchard (n = 165). Thus, the vast majority of shared clones existed on individual leaflets on a terminal at the scale of 10s of centimeters or less, indicating a notable component of short-distance dispersal. There was significant linkage disequilibrium (P < 0.001), and an analysis of Psex showed that where there were multiple encounters of an MLG, they were most probably the result of asexual reproduction (P < 0.05) but there was no evidence that asexual reproduction was involved in single or first encounters of an MLG (P > 0.05). Overall, the MAT1-1-1 and MAT1-2-1 idiomorphs were at equilibrium (73:92) and in most populations, subpopulations, and sub-subpopulations. Both mating types were frequently observed on the same leaflet. The results provide novel information on the characteristics of populations of V. effusa at fine spatial scales, and provide insights into the dispersal of the organism within and between trees. The proximity of both mating idiomorphs on single leaflets is further evidence of opportunity for development of the sexual stage in the field.

Sign in / Sign up

Export Citation Format

Share Document