scholarly journals Gene flow on ice: the role of sea ice and whaling in shaping Holarctic genetic diversity and population differentiation in bowhead whales (Balaena mysticetus)

2012 ◽  
Vol 2 (11) ◽  
pp. 2895-2911 ◽  
Author(s):  
S. Elizabeth Alter ◽  
Howard C. Rosenbaum ◽  
Lianne D. Postma ◽  
Peter Whitridge ◽  
Cork Gaines ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Sea Ice ◽  
Population Differentiation ◽  
Balaena Mysticetus ◽  
Bowhead Whales

scholarly journals Genetic Diversity and Population Differentiation ofGuignardia mangiferaefrom “Tahiti” Acid Lime

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Ester Wickert ◽  
Eliana Gertrudes de Macedo Lemos ◽  
Luciano Takeshi Kishi ◽  
Andressa de Souza ◽  
Antonio de Goes
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Population Differentiation ◽  
Black Spot ◽  
The Other ◽  
Presenting Symptoms ◽  
Citrus Black Spot ◽  
Panmictic Population ◽  
Acid Lime

Among the citrus plants, “Tahiti” acid lime is known as a host ofG. mangiferaefungi. This species is considered endophytic for citrus plants and is easily isolated from asymptomatic fruits and leaves.G. mangiferaeis genetically related and sometimes confused withG. citricarpawhich causes Citrus Black Spot (CBS). “Tahiti” acid lime is one of the few species that means to be resistant to this disease because it does not present symptoms. Despite the fact that it is commonly found in citric plants, little is known about the populations ofG. mangiferaeassociated with these plants. Hence, the objective of this work was to gain insights about the genetic diversity of theG. mangiferaepopulations that colonize “Tahiti” acid limes by sequencing cistron ITS1-5.8S-ITS2. It was verified that “Tahiti” acid lime plants are hosts ofG. mangiferaeand also ofG. citricarpa, without presenting symptoms of CBS. Populations ofG. mangiferaepresent low-to-moderate genetic diversity and show little-to-moderate levels of population differentiation. As gene flow was detected among the studied populations and they share haplotypes, it is possible that all populations, from citrus plants and also from the other known hosts of this fungus, belong to one great panmictic population.

scholarly journals Genetic Diversity and Structure of the Apiosporina morbosa Populations on Prunus spp.

2005 ◽  
Vol 95 (8) ◽  
pp. 859-866 ◽  
Author(s):  
Jinxiu Zhang ◽  
W. G. Dilantha Fernando ◽  
William. R. Remphrey
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Gene Flow ◽  
Host Species ◽  
Population Differentiation ◽  
The United States ◽  
Flow Rates ◽  
Geographic Locations ◽  
Genetic Diversity And Structure ◽  
Geographic Populations

Populations of Apiosporina morbosa collected from 15 geographic locations in Canada and the United States and three host species, Prunus virginiana, P. pensylvanica, and P. padus, were evaluated using the sequence-related amplified polymorphism (SRAP) technique to determine their genetic diversity and population differentiation. Extensive diversity was detected in the A. morbosa populations, including 134 isolates from Canada and the United States, regardless of the origin of the population. The number of polymorphic loci varied from 6.9 to 82.8% in the geographic populations, and from 41.4 to 79.3% in the populations from four host genotypes based on 58 polymorphic fragments. In all, 44 to 100% of isolates in the geographic populations and 43.6 to 76.2% in populations from four host genotypes represented unique genotypes. Values of heterozygosity (H) varied from 2.8 to 28.3% in the geographic populations and 10.2 to 26.1% in the populations from four host genotypes. In general, the A. morbosa populations sampled from wild chokecherry showed a higher genetic diversity than those populations collected from other host species, whereas the populations isolated from cultivated chokecherry, P. virginiana ‘Shubert Select’, showed a reduction of genetic diversity compared with populations from wild P. virginiana. Significant population differentiation was found among both the geographic populations (P < 0.05) and populations from different host genotypes (P < 0.02). In the geographic populations, most of populations from cultivated and wild P. virginiana were closely clustered, and no population differentiation was detected except for the populations from Morris, Morden, and Winnipeg, Manitoba, Canada. Furthermore, the populations from P. virginiana in the same geographic locations had higher genetic identity and closer genetic distance to each other compared with those from different locations. Four populations from P. virginiana, P. pensylvanica, and P. padus, were significantly differentiated from each other (P < 0.02), except there was no differentiation between the Shubert Select and wild chokecherry populations (>P> = 0.334). Indirect estimation of gene flow showed that significant restricted gene flow existed between populations from different regions and host species. Gene flow rates (Nm) varied from <1 to 12.5, with higher gene flow rates among population pairs from the same host species (P = 1.000). The analysis of molecular variance revealed that a major genetic variance source came from the genetic variation among isolates within populations regardless of the origin and host genotype of the population. Although some locations had a limited number of isolates, the results of this study clearly showed that the genetic diversity and population differentiation of A. morbosa were closely associated with host genotypes and geographic locations, but mostly with the former.

scholarly journals Landscape and climatic features drive genetic differentiation processes in a South American coastal plant

2020 ◽  
Author(s):  
Gustavo A. Silva-Arias ◽  
Lina Caballero-Villalobos ◽  
Giovanna C. Giudicelli ◽  
Loreta B. Freitas
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Coastal Plain ◽  
Population Differentiation ◽  
Water Bodies ◽  
Marginal Populations ◽  
Landscape Features ◽  
Precipitation Seasonality ◽  
Isolation By Environment

ABSTRACTBackground and aimsHistorical and ecological processes shaped the patterns of genetic diversity in plant species; among these, colonization to new environments such as coastal regions generate multiple signals of interest to understand the influence of landscape features on the population differentiation.MethodsWe analysed the genetic diversity and population structure of Calibrachoa heterophylla to infer the influence of abiotic landscape features on this coastal species’ gene flow in the South Atlantic Coastal Plain (SACP). We used ten microsatellite loci to genotype 253 individuals from 15 populations, covering the species’ entire geographical range. We applied population genetics analyses to determine population diversity and structure along the SACP, migration model inference and correlative analyses to disentangle the most likely drivers of gene flow in the SACP.Key ResultsThe C. heterophylla populations located more distantly from the seashore showed higher genetic diversity than those closer to the sea. The genetic differentiation had a consistent signal of isolation-by-distance. Landscape features, such as water bodies and wind corridors, and raw geographical distances equally explained the genetic differentiation, whereas the precipitation seasonality showed a strong signal for isolation-by-environment in marginal populations. The estimated gene flow suggested that marginal populations had restricted immigration rates, which could enhance the genetic differentiation.ConclusionsThe influence of topographical features in population differentiation in C. heterophylla is related with the history of the coastal plain deposition. Gene flow is mainly restricted to nearby populations and facilitated by wind fields but with no apparent influence of large water bodies. Furthermore, differential rainfall regimes in marginal populations can promote local genetic differentiation.

scholarly journals Genetic Diversity and Gene Flow of Quercus crispula in a Semi-Fragmented Forest Together With Neighboring Forests

2006 ◽  
Vol 55 (1-6) ◽  
pp. 160-169 ◽  
Author(s):  
Takafumi Ohsawa ◽  
Y. Tsuda ◽  
Y. Saito ◽  
H. Sawada ◽  
Y. Ide
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Population Differentiation ◽  
Pollen Dispersal ◽  
Parentage Analysis ◽  
Natural Forest ◽  
Central Japan ◽  
Quercus Crispula ◽  
Fragmented Forest ◽  
Fragmented Forests

Abstract The genetic diversity and differentiation in Quercus crispula populations in the Chichibu Mountains, central Japan, were evaluated using six microsatellite markers. Gene flow into a 2500-m2 semi-fragment of a natural forest from the neighboring natural forest at a distance of more than 50m was also evaluated using parentage analysis. All five populations in the mountains had similar levels of genetic diversity (He = 0.752-0.792), and the level of population differentiation was low (FST = 0.016). The semi-fragmented stand showed similar genetic diversity with the neighboring unfragmented forests, and Hardy-Weinberg disequilibrium was not found (FIS = 0.083 in adults, 0.025 in seedlings). In the semifragment, 70 seedlings were examined; according to the parentage analysis, eight of the 70 seedlings (ca. 11%) had neither of the parent trees in this fragment. These seeds must have been transported from a distance of more than 50 m; therefore, there could be a possibility that the seeds were dispersed by birds. A similar trend of seed flow into the fragment was also confirmed by genotyping endocarps of hypogeal cotyledons, while more frequent seed flow was found in the neighboring unfragmented forest. Of the remaining 62 seedlings, the maternal trees (but not the paternal trees) of 29 seedlings and both parent trees of 33 seedlings were detected in the semi-fragment. These results indicate that the gene flow among the populations occurs frequently via pollen dispersal and occasionally via seed dispersal and that, at least the current levels of genetic diversity have been maintained in such fragmented forests.

scholarly journals Sea ice reduction drives genetic differentiation among Barents Sea polar bears

2021 ◽  
Vol 288 (1958) ◽  
pp. 20211741 ◽  
Author(s):  
Simo Njabulo Maduna ◽  
Jon Aars ◽  
Ida Fløystad ◽  
Cornelya F. C. Klütsch ◽  
Eve M. L. Zeyl Fiskebeck ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Sea Ice ◽  
Barents Sea ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Polar Bears ◽  
Negative Consequences ◽  
Svalbard Archipelago

Loss of Arctic sea ice owing to climate change is predicted to reduce both genetic diversity and gene flow in ice-dependent species, with potentially negative consequences for their long-term viability. Here, we tested for the population-genetic impacts of reduced sea ice cover on the polar bear ( Ursus maritimus ) sampled across two decades (1995–2016) from the Svalbard Archipelago, Norway, an area that is affected by rapid sea ice loss in the Arctic Barents Sea. We analysed genetic variation at 22 microsatellite loci for 626 polar bears from four sampling areas within the archipelago. Our results revealed a 3–10% loss of genetic diversity across the study period, accompanied by a near 200% increase in genetic differentiation across regions. These effects may best be explained by a decrease in gene flow caused by habitat fragmentation owing to the loss of sea ice coverage, resulting in increased inbreeding of local polar bears within the focal sampling areas in the Svalbard Archipelago. This study illustrates the importance of genetic monitoring for developing adaptive management strategies for polar bears and other ice-dependent species.

Genetic rescue by augmenting gene flow

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Inbreeding Coefficient ◽  
Outbreeding Depression ◽  
Genetic Rescue ◽  
Evolutionary Potential ◽  
Beneficial Effects ◽  
The Difference ◽  
Inbred Populations ◽  
Harmful Effects

Inbreeding is reduced and genetic diversity enhanced when a small isolated inbred population is crossed to another unrelated population. Crossing can have beneficial or harmful effects on fitness, but beneficial effects predominate, and the risks of harmful ones (outbreeding depression) can be predicted and avoided. For crosses with a low risk of outbreeding depression, there are large and consistent benefits on fitness that persist across generations in outbreeding species. Benefits are greater in species that naturally outbreed than those that inbreed, and increase with the difference in inbreeding coefficient between crossed and inbred populations in mothers and zygotes. However, benefits are similar across invertebrates, vertebrates and plants. There are also important benefits for evolutionary potential of crossing between populations.

scholarly journals Mitogenomics of the endangered Mediterranean monk seal (Monachus monachus) reveals dramatic loss of diversity and supports historical gene-flow between Atlantic and eastern Mediterranean populations

2020 ◽  
Author(s):  
Alba Rey-Iglesia ◽  
Philippe Gaubert ◽  
Gonçalo Espregueira Themudo ◽  
Rosa Pires ◽  
Constanza De La Fuente ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
North Atlantic ◽  
Marine Mammals ◽  
Eastern Mediterranean ◽  
The Black Sea ◽  
Mediterranean Populations ◽  
Geographic Ranges ◽  
Western Sahara ◽  
The Mediterranean

Abstract The Mediterranean monk seal Monachus monachus is one of the most threatened marine mammals, with only 600–700 individuals restricted to three populations off the coast of Western Sahara and Madeira (North Atlantic) and between Greece and Turkey (eastern Mediterranean). Its original range was from the Black Sea (eastern Mediterranean) to Gambia (western African coast), but was drastically reduced by commercial hunting and human persecution since the early stages of marine exploitation. We here analyse 42 mitogenomes of Mediterranean monk seals, from across their present and historical geographic ranges to assess the species population dynamics over time. Our data show a decrease in genetic diversity in the last 200 years. Extant individuals presented an almost four-fold reduction in genetic diversity when compared to historical specimens. We also detect, for the first time, a clear segregation between the two North Atlantic populations, Madeira and Cabo Blanco, regardless of their geographical proximity. Moreover, we show the presence of historical gene-flow between the two water basins, the Atlantic Ocean and the Mediterranean Sea, and the presence of at least one extinct maternal lineage in the Mediterranean. Our work demonstrates the advantages of using full mitogenomes in phylogeographic and conservation genomic studies of threatened species.

Trends in Arctic sea ice and the role of atmospheric circulation

2013 ◽  
Vol 14 (2) ◽  
pp. 97-101 ◽  
Author(s):  
Masayo Ogi ◽  
Ignatius G. Rigor
Keyword(s):  
Sea Ice ◽  
Atmospheric Circulation ◽  
Arctic Sea Ice ◽  
Arctic Sea
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