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

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

The Scientific World JOURNAL ◽

10.1100/2012/125654 ◽

2012 ◽

Vol 2012 ◽

pp. 1-11 ◽

Cited By ~ 2

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.

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

Phytopathology ◽

10.1094/phyto-95-0859 ◽

2005 ◽

Vol 95 (8) ◽

pp. 859-866 ◽

Cited By ~ 8

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.

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

10.1101/2020.07.02.184366 ◽

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.

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Pollen and seed dispersal of Brazil nut trees in the southwestern Brazilian Amazon

Acta Amazonica ◽

10.1590/1809-4392201800021 ◽

2018 ◽

Vol 48 (3) ◽

pp. 217-223

Author(s):

Karina MARTINS ◽

Raifanny da Silva Oliveira dos SANTOS ◽

Tatiana de CAMPOS ◽

Lúcia Helena de Oliveira WADT

Keyword(s):

Genetic Diversity ◽

Seed Dispersal ◽

Pollen Dispersal ◽

Brazilian Amazon ◽

Parentage Analysis ◽

Fixation Index ◽

Gene Dispersal ◽

Dispersal Capacity ◽

Pollen And Seed Dispersal ◽

Natural Stands

ABSTRACT Pollen and seed dispersal patterns greatly influence the spatial distribution of plant genetic diversity. Microsatellite-based parentage analysis provides accurate estimates of contemporary gene dispersal. Although most tropical trees have been shown to exhibit widespread pollen dispersal, few studies have estimated contemporary gene dispersal after seedling establishment. Bertholletia excelsa (Lecythidaceae) is pollinated by large-bodied bees, while previous seed-tracking experiments suggest their seeds are mainly dispersed across very short distances by scatter-hoarding rodents, who primarily act as seed predators. Here we used parentage analysis to provide contemporary estimates of pollen and seed dispersal in B. excelsa recruits. We examined six 25-ha plots located in two natural stands in the Acre River valley, in the southwestern Brazilian Amazon. We used 11 microsatellite markers to estimate genetic diversity and fixation index parameters in adults, seedlings and saplings. Genetic diversity was moderate and did not differ across size classes or sampling locations. We assigned pollen and seed parents for < 20% of the recruits, indicating that most events of realized gene flow occurred beyond our 25-ha plots. Only 10 parentage assignments were confirmed with 80% confidence. Pollen distance ranged from 33 to 372 m and seed dispersal from 58 to 655 m. Actual seed-dispersal distances were far greater than the estimates obtained in previous seed-tracking experiments. Thus, studies encompassing larger sampling areas are necessary to determine a more representative spatial scale of B. excelsa’s pollen and seed dispersal capacity in natural stands.

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The relative contributions of seed and pollen dispersal to gene flow and genetic diversity in seedlings of a tropical palm

Molecular Ecology ◽

10.1111/mec.14768 ◽

2018 ◽

Vol 27 (15) ◽

pp. 3159-3173 ◽

Cited By ~ 6

Author(s):

Luke Browne ◽

Kym Ottewell ◽

Victoria L. Sork ◽

Jordan Karubian

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Pollen Dispersal

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Genetic diversity of Dactylorhiza incarnata (Orchidaceae) in northern Poland

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.3496 ◽

2016 ◽

Vol 85 (2) ◽

Cited By ~ 3

Author(s):

Aleksandra M. Naczk ◽

Igor J. Chybicki ◽

Marek S. Ziętara

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Genetic Structure ◽

Genetic Differentiation ◽

Pollen Dispersal ◽

Species Level ◽

Bottleneck Effect ◽

Northern Poland ◽

Habitat Loss And Fragmentation ◽

Population Numbers

The genetic structure of Dactylorhiza incarnata var. incarnata populations is shaped not only by historical events such as recolonization after ice sheet retreat or limited seed and pollen dispersal, but also the bottleneck effect. During the last decade, D. incarnata var. incarnata has also experienced a strong decline in population numbers and sizes, due to habitat loss and fragmentation. In the present research genetic diversity was examined in eight populations located in northern Poland, using six nuclear microsatellites loci. At the species level our results showed a moderate mean level of genetic diversity (A = 4.67; Ae = 2.73; Rs = 4.48; Ho = 0.438; FIS = 0.224), which varied among the studied populations (A: 2.17–3.67; Ae: 1.55–2.69; Rs: 1.31–1.61; Ho: 0.292–0.631; FIS: −0.283–0.340). A considerable overabundance of homozygotes was detected in four populations (FIS within the range of 0.067–0.340), and in the remaining populations an excess of heterozygotes was observed. The average apparent out-crossing rate was also calculated (ta = 0.980), and primarily indicated a tendency to out-cross within the species. Moderate genetic differentiation was found among the studied populations (FST = 0.149; RST = 0.174; p < 0.05). The differentiation of the populations corresponded to relatively low gene flow value (Nm = 0.426) among populations, which amounted to only one migrant every second generation.

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

Ecology and Evolution ◽

10.1002/ece3.397 ◽

2012 ◽

Vol 2 (11) ◽

pp. 2895-2911 ◽

Cited By ~ 25

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

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Genetic rescue by augmenting gene flow

10.1093/oso/9780198783398.003.0006 ◽

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.

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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

Zoological Journal of the Linnean Society ◽

10.1093/zoolinnean/zlaa084 ◽

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.

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