Pollen-mediated gene flow and fine-scale spatial genetic structure inOlea europaeasubsp.europaeavar.sylvestris

Abstract Understanding the impact of management on the dispersal potential of forest tree species is pivotal in the context of global change, given the implications of gene flow on species evolution. We aimed to determine the effect of logging on gene flow distances in two Nothofagus species from temperate Patagonian forests having high ecological relevance and wood quality. Therefore, a total of 778 individuals (mature trees and saplings) of Nothofagus alpina and N. obliqua, from a single plot managed 20 years ago (2.85 hectares), were mapped and genotyped at polymorphic nuclear microsatellite loci. Historical estimates of gene dispersal distance (based on fine-scale spatial genetic structure) and contemporary estimates of seed and pollen dispersal (based on spatially explicit mating models) were obtained. The results indicated restricted gene flow (gene distance ≤ 45 m, both pollen and seed), no selfing and significant seed and pollen immigration from trees located outside the studied plot but in the close surrounding area. The size of trees (diameter at breast height and height) was significantly associated with female and/or male fertility. The significant fine-scale spatial genetic structure was consistent with the restricted seed and pollen dispersal. Moreover, both estimates of gene dispersal (historical and contemporary) gave congruent results. This suggests that the recent history of logging within the study area has not significantly influenced on patterns of gene flow, which can be explained by the silviculture applied to the stand. The residual tree density maintained species composition, and the homogeneous spatial distribution of trees allowed the maintenance of gene dispersal. The short dispersal distance estimated for these two species has several implications both for understanding the evolution of the species and for defining management, conservation and restoration actions. Future replication of this study in other Nothofagus Patagonian forests would be helpful to validate our conclusions.

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Gene flow and fine-scale spatial genetic structure in Cabralea canjerana (Meliaceae), a common tree species from the Brazilian Atlantic forest

Journal of Tropical Ecology ◽

10.1017/s0266467416000067 ◽

2016 ◽

Vol 32 (2) ◽

pp. 135-145 ◽

Cited By ~ 7

Author(s):

Arthur Tavares de Oliveira Melo ◽

Edivani Villaron Franceschinelli

Keyword(s):

Gene Flow ◽

Genetic Structure ◽

Atlantic Forest ◽

Tree Species ◽

Spatial Genetic Structure ◽

Molecular Ecology ◽

Spatial Distance ◽

Forest Fragments ◽

Fine Scale ◽

Flow Process

Abstract:The Atlantic forest is the biome most severely affected by deforestation in Brazil. Cabralea canjerana spp. canjerana is a dioecious tree species with widespread distribution in the Neotropical region. This species is considered a model to ascertain population ecology parameters for endangered plant species from the Atlantic forest. Fine-scale spatial genetic structure and pollen-mediated gene flow are crucial information in landscape genetics and evolutionary ecology. A total of 192 adults and 121 offspring were sampled in seven C. canjerana populations in the Southern Minas Gerais State, Brazil, to assess whether pollen-mediated gene flow is able to prevent spatial genetic structure within and among Atlantic forest fragments. Several molecular ecology parameters were estimated using microsatellite loci. High levels of genetic diversity (HE = 0.732) and moderate population structure (θ = 0.133) were recorded. No significant association between kinship and spatial distance amongst individuals within each population (Sp = 0.000109) was detected. Current pollen-mediated gene flow occurs mainly within forest fragments, probably due to short-distance flights of the pollinator of C. canjerana, and also the forest fragmentation may have restricted flight distance. The high levels of genetic differentiation found amongst the seven sites sampled demonstrated how habitat fragmentation affects the gene flow process in natural areas.

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Fine-scale spatial genetic structure and gene flow in a small, fragmented population of Sinojackia rehderiana (Styracaceae), an endangered tree species endemic to China

Plant Biology ◽

10.1111/j.1438-8677.2010.00361.x ◽

2011 ◽

Vol 13 (2) ◽

pp. 401-410 ◽

Cited By ~ 12

Author(s):

X. Yao ◽

J. Zhang ◽

Q. Ye ◽

H. Huang

Keyword(s):

Gene Flow ◽

Genetic Structure ◽

Tree Species ◽

Spatial Genetic Structure ◽

Fine Scale ◽

Endangered Tree ◽

Endangered Tree Species ◽

Fragmented Population

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Spatial genetic structure of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) at the northern limit of their native range

Canadian Journal of Zoology ◽

10.1139/cjz-2019-0183 ◽

2020 ◽

Vol 98 (5) ◽

pp. 317-330

Author(s):

Samuel Deakin ◽

Jamieson C. Gorrell ◽

Jeffery Kneteman ◽

David S. Hik ◽

Richard M. Jobin ◽

...

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Genetic Structure ◽

Rocky Mountains ◽

Spatial Genetic Structure ◽

Rocky Mountain ◽

Bighorn Sheep ◽

Ovis Canadensis ◽

Fine Scale ◽

Northern Portion

The Canadian Rocky Mountains are one of the few places on Earth where the spatial genetic structure of wide-ranging species has been relatively unaffected by anthropogenic disturbance. We characterized the spatial genetic structure of Rocky Mountain bighorn sheep (Ovis canadensis canadensis Shaw, 1804) in the northern portion of their range. Using microsatellites from 1495 individuals and mitochondrial DNA sequences from 188 individuals, we examined both broad- and fine-scale spatial genetic structure, assessed sex-biased gene flow within the northern portion of the species range, and identified geographic patterns of genetic diversity. We found that broad-scale spatial genetic structure was consistent with barriers to movement created by major river valleys. The fine-scale spatial genetic structure was characterized by a strong isolation-by-distance pattern, and analysis of neighborhood size using spatial autocorrelation indicated gene flow frequently occurred over distances of up to 100 km. However, analysis of sex-specific spatial autocorrelation and analysis of mitochondrial haplotype distributions failed to detect any evidence of sex-biased gene flow. Finally, our analyses reveal decreasing genetic diversity with increasing latitude, consistent with patterns of post-glacial recolonization of the Rocky Mountains.

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Fine-Scale Patterns of Genetic Structure in the Host Plant Chamaecrista fasciculata (Fabaceae) and Its Nodulating Rhizobia Symbionts

Plants ◽

10.3390/plants9121719 ◽

2020 ◽

Vol 9 (12) ◽

pp. 1719

Author(s):

Mahboubeh Hosseinalizadeh Nobarinezhad ◽

Lisa E. Wallace

Keyword(s):

Gene Flow ◽

Genetic Structure ◽

Spatial Autocorrelation ◽

Host Plant ◽

Host Plants ◽

Spatial Genetic Structure ◽

Genetic Identity ◽

Fine Scale ◽

Chamaecrista Fasciculata ◽

Limited Gene Flow

In natural plant populations, a fine-scale spatial genetic structure (SGS) can result from limited gene flow, selection pressures or spatial autocorrelation. However, limited gene flow is considered the predominant determinant in the establishment of SGS. With limited dispersal ability of bacterial cells in soil and host influence on their variety and abundance, spatial autocorrelation of bacterial communities associated with plants is expected. For this study, we collected genetic data from legume host plants, Chamaecrista fasciculata, their Bradyrhizobium symbionts and rhizosphere free-living bacteria at a small spatial scale to evaluate the extent to which symbiotic partners will have similar SGS and to understand how plant hosts choose among nodulating symbionts. We found SGS across all sampled plants for both the host plants and nodulating rhizobia, suggesting that both organisms are influenced by similar mechanisms structuring genetic diversity or shared habitat preferences by both plants and microbes. We also found that plant genetic identity and geographic distance might serve as predictors of nodulating rhizobia genetic identity. Bradyrhizobium elkanii was the only type of rhizobia found in nodules, which suggests some level of selection by the host plant.

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