Effects of seed dispersal on spatial genetic structure in populations of Rutidosis leptorrhychoides with different levels of correlated paternity

Rutidosis leptorrynchoides is a perennial forb endemic to grasslands and grassy woodlands in southeastern Australia. Studies of seed dispersal, spatial genetic structure and clonality were carried out in four populations around the Canberra region that varied in levels of correlated paternity to examine: (1) whether R. leptorrhynchoides populations exhibit fine-scale spatial genetic structure and whether this varies between populations as a function of correlated paternity; (2) whether there is a correlation between seed dispersal distance and genetic relatedness within populations; and (3) whether clonal reproduction occurs in this species and to what degree this could account for the observed spatial genetic structure. The results show that there is variation in the magnitude and extent of spatial genetic structure between R. leptorrhynchoides populations. The three larger populations, with low to moderate full-sib proportions, showed significant patterns of coancestry between plants over scales of up to one metre, whereas the smallest population, with a high full-sib proportion, had erratically high but non-significant coancestry values. The observed patterns of genetic clumping could be explained by a combination of limited seed dispersal and correlated mating owing to limited mate availability resulting from the species' sporophytic self-incompatibility system. Clonality does not appear to be an important factor contributing to genetic structure in this species.

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Gene dispersal via seeds and pollen and their effects on genetic structure in the facultative-apomictic Neotropical tree Aspidosperma polyneuron

Silvae Genetica ◽

10.1515/sg-2016-0016 ◽

2016 ◽

Vol 65 (2) ◽

pp. 46-57 ◽

Cited By ~ 1

Author(s):

C. L. Chaves ◽

A. M. Sebbenn ◽

A. Baranoski ◽

B. D. Goez ◽

A. P.S.C. Gaino ◽

...

Keyword(s):

Genetic Structure ◽

Seed Dispersal ◽

Sexual Reproduction ◽

Isolation By Distance ◽

Spatial Genetic Structure ◽

Dispersal Distance ◽

Pollen Flow ◽

Gene Dispersal ◽

Asexual Propagation ◽

Neotropical Tree

Abstract Facultative apomictic trees can produce offspring with a genotype identical to the mother due to asexual propagation through the embryo derived from cells in the maternal ovule tissues. These trees can also produce offspring with a genotype different from the mother due to genetic recombination. For many trees, these reproductive processes remain largely unexplored. Herein, we use microsatellite markers to identify apomictic and sexual reproduction in samples of adult and juvenile trees of the tropical, insect pollinated and wind seed dispersed Aspidosperma polyneuron, within a conservation area in Brazil. We also investigate seed and pollen flow and dispersal patterns and compare the genetic diversity, inbreeding, and intrapopulation spatial genetic structure (SGS) between adults and juveniles in two plots. Our results show that the species present both apomictic and sexual reproduction. Sexual reproduction occurred mainly by outcrossing, but we did detect instances of self-fertilization and mating among relatives, which explains the inbreeding observed in juveniles. Seed dispersal distance was shorter than pollen dispersal distance in one of the plots, suggesting that insect vectors are more efficient in gene dispersal than wind for seed dispersal in a high density tropical forest. The patterns of pollen and seed dispersal showed isolation by distance, explaining the SGS detected for adults and juveniles. Our results show that both seed and pollen flow increase the allelic diversity in the population. The regeneration of apomictic individuals may guarantee the continuation of genotypes adapted specifically to the study site, while sexual reproduction results in new genotypes.

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Effects of seed dispersal, adult tree and seedling density on the spatial genetic structure of regeneration at fine temporal and spatial scales

Tree Genetics & Genomes ◽

10.1007/s11295-010-0313-y ◽

2010 ◽

Vol 7 (1) ◽

pp. 37-48 ◽

Cited By ~ 32

Author(s):

Fabrice Sagnard ◽

Sylvie Oddou-Muratorio ◽

Christian Pichot ◽

Giovanni G. Vendramin ◽

Bruno Fady

Keyword(s):

Genetic Structure ◽

Seed Dispersal ◽

Spatial Genetic Structure ◽

Spatial Scales ◽

Seedling Density ◽

Adult Tree ◽

Temporal And Spatial

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Staying close: short local dispersal distances on a managed forest of two Patagonian Nothofagus species

Forestry An International Journal of Forest Research ◽

10.1093/forestry/cpaa008 ◽

2020 ◽

Vol 93 (5) ◽

pp. 652-661 ◽

Cited By ~ 2

Author(s):

Georgina Sola ◽

Verónica El Mujtar ◽

Leonardo Gallo ◽

Giovanni G Vendramin ◽

Paula Marchelli

Keyword(s):

Gene Flow ◽

Genetic Structure ◽

Spatial Genetic Structure ◽

Pollen Dispersal ◽

Dispersal Distance ◽

Restricted Gene Flow ◽

Fine Scale ◽

Gene Dispersal ◽

Mature Trees ◽

The Impact

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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Contrasting impacts of pollen and seed dispersal on spatial genetic structure in the bird-pollinated Banksia hookeriana

Heredity ◽

10.1038/hdy.2008.118 ◽

2008 ◽

Vol 102 (3) ◽

pp. 274-285 ◽

Cited By ~ 46

Author(s):

S L Krauss ◽

T He ◽

L G Barrett ◽

B B Lamont ◽

N J Enright ◽

...

Keyword(s):

Genetic Structure ◽

Seed Dispersal ◽

Spatial Genetic Structure ◽

Pollen And Seed Dispersal

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Effect of balancing selection on spatial genetic structure within populations: theoretical investigations on the self-incompatibility locus and empirical studies in Arabidopsis halleri

Heredity ◽

10.1038/hdy.2010.68 ◽

2010 ◽

Vol 106 (2) ◽

pp. 319-329 ◽

Cited By ~ 17

Author(s):

J-B Leducq ◽

V Llaurens ◽

V Castric ◽

P Saumitou-Laprade ◽

O J Hardy ◽

...

Keyword(s):

Genetic Structure ◽

Balancing Selection ◽

Spatial Genetic Structure ◽

Empirical Studies ◽

The Self ◽

Self Incompatibility ◽

Arabidopsis Halleri ◽

Theoretical Investigations ◽

Incompatibility Locus

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Microsatellite analyses of spatial genetic structure in darkblotched rockfish (Sebastes crameri): Is pooling samples safe?

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f05-084 ◽

2005 ◽

Vol 62 (8) ◽

pp. 1874-1886 ◽

Cited By ~ 14

Author(s):

Daniel Gomez-Uchida ◽

Michael A Banks

Keyword(s):

Genetic Structure ◽

Isolation By Distance ◽

Spatial Genetic Structure ◽

Geographic Distance ◽

Original Data ◽

Dispersal Distance ◽

Data Set ◽

Limited Dispersal ◽

Composite Samples ◽

Microsatellite Analyses

By pooling or removing samples of small size, we investigated how results from microsatellite analyses of spatial genetic structure in darkblotched rockfish (Sebastes crameri) were affected. Genotypes from six and seven microsatellite loci from 1206 specimens collected offshore from Washington to California were employed in the analyses. Sample sizes varied greatly among locations (n = 11114). When adjacent samples of n < 25 were pooled using an absolute genetic distance (FST ≤ 0), the correlation between genetic and geographic distance found in the original data set increased nearly twofold, and overall FST (95% confidence interval) increased from 0.001 (0.0000.002) to 0.002 (0.0010.003). Removing samples where n < 25 gave a similar result, yet the correlation increase was smaller. Another pooling strategy based on similarity tests allowed larger sizes in composite samples (n > 100) and further increased the correlation, although this strategy did not raise overall FST. These results indicate that under genetic isolation by distance, excessive pooling might not enhance the overall genetic differentiation among populations. The regression slope in isolation by distance plots was robust throughout all treatments, and its value suggests limited dispersal distance on this species.

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Small-scale spatial genetic structure of Asarum sieboldii metapopulation in a valley

Journal of Ecology and Environment ◽

10.1186/s41610-021-00186-x ◽

2021 ◽

Vol 45 (1) ◽

Author(s):

Hyeon Jin Jeong ◽

Jae Geun Kim

Keyword(s):

Genetic Diversity ◽

Genetic Structure ◽

Genetic Differentiation ◽

Genetic Distance ◽

Spatial Genetic Structure ◽

Dispersal Distance ◽

Forest Understory ◽

Small Scale ◽

Low Density ◽

Stochastic Events

Abstract Background Asarum sieboldii Miq., a species of forest understory vegetation, is an herbaceous perennial belonging to the family Aristolochiaceae. The metapopulation of A. sieboldii is distributed sparsely and has a short seed dispersal distance by ants as their seed distributor. It is known that many flowers of A. sieboldii depend on self-fertilization. Because these characteristics can affect negatively in genetic structure, investigating habitat structure and assessment of genetic structure is needed. A total of 27 individuals in a valley were sampled for measuring genetic diversity, genetic distance, and genetic differentiation by RAPD-PCR. Results The habitat areas of A. sieboldii metapopulation were relatively small (3.78~33.60 m2) and population density was very low (five to seven individuals in 20×20 m quadrat). The habitat of A. sieboldii was a very shady (relative light intensity = 0.9%) and mature forest with a high evenness value (J = 0.81~0.99) and a low dominance value (D = 0.19~0.28). The total genetic diversity of A. sieboldii was quite high (h = 0.338, I = 0.506). A total of 33 band loci were observed in five selected primers, and 31 band loci (94%) were polymorphic. However, genetic differentiation along the valley was highly progressed (Gst = 0.548, Nm = 0.412). The average genetic distance between subpopulations was 0.387. The results of AMOVA showed 52.77% of variance occurs among populations, which is evidence of population structuring. Conclusions It is expected that a small-scale founder effect had occurred, an individual spread far from the original subpopulation formed a new subpopulation. However, geographical distance between individuals would have been far and genetic flow occurred only within each subpopulation because of the low density of population. This made significant genetic distance between the original and new population by distance. Although genetic diversity of A. sieboldii metapopulation is not as low as concerned, the subpopulation of A. sieboldii can disappear by stochastic events due to small subpopulation size and low density of population. To prevent genetic isolation and to enhance the stable population size, conservative efforts such as increasing the size of each subpopulation or the connection between subpopulations are needed.

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Gene flow in an overexploited population of Swietenia macrophylla King (Meliaceae) in the Bolivian Amazon

Silvae Genetica ◽

10.1515/sg-2012-0027 ◽

2012 ◽

Vol 61 (1-6) ◽

pp. 212-220 ◽

Cited By ~ 6

Author(s):

A. M. Sebbenn ◽

J. C. Licona ◽

B. Mostacedo ◽

B. Degen

Keyword(s):

Genetic Structure ◽

Spatial Genetic Structure ◽

Pollen Dispersal ◽

Dispersal Distance ◽

Fixation Index ◽

Permanent Plots ◽

Swietenia Macrophylla ◽

Genetic Structure Of Populations ◽

Bolivian Amazon ◽

Adult Trees

Abstract Pollen and seed movement among and within populations connect individuals and populations, and therefore are among the most important evolutionary processes determining the genetic structure of populations. Seven microsatellite loci were used to investigate the realized pollen dispersal and intra-population spatial genetic structure (SGS) in four permanent plots located in an overexploited big-leaf mahogany (Swietenia macrophylla King) population in the Bolivian Amazon. All adult trees found in the plots were mapped, sampled and genotyped. Seedlings were sampled below the canopy of reproductive trees. Private alleles in the sub-population of the adults and the seedlings were observed. The observed heterozygosity was significantly lower and fixation index was significantly higher for the seedlings (Ho=0.697, F=0.068) compared to the adults (Ho=0.761, F=-0.023). In one plot, seed immigration was observed (18%). Realized pollen immigration ranged among the plots from zero to 41% and selfing ranged from zero to 5.8%. We observed an average pollen dispersal distance from 75 to 255 m, with the maximum reaching 576 m. We found a significant SGS up to 150 m, showing that near neighbour individuals are relatives. The observed data on pollen- and seed dispersal provides important information for the sustainable management of the endangered mahogany species.

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Genetic variation in Armeria maritima in Iceland

Polar Record ◽

10.1017/s0032247400017745 ◽

2002 ◽

Vol 38 (206) ◽

pp. 219-224

Author(s):

Marianne Philipp

Keyword(s):

Genetic Variation ◽

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Gene Diversity ◽

The Self ◽

Self Incompatibility ◽

Rare Alleles ◽

Incompatibility System ◽

Armeria Maritima

AbstractA comparison of the population genetic structure of Armeria maritima in Iceland with an earlier study in Denmark was undertaken. Ten populations were sampled in Iceland for isozyme analysis. Most populations showed Hardy-Weinberg proportions, but a higher number than statistically expected possessed too many homozygotes. This could indicate a breakdown of the self-incompatibility system in some cases. Statistically significant differences in allelic frequencies among populations were observed but no positive correlation between genetic distance and geographic position was found. Gene diversity in Iceland was lower than in Denmark although the alleles occurring in Iceland were the same as those found in Denmark. Missing alleles were those found with lowest frequency in Denmark. It is suggested that A. maritima in Iceland has immigrated from the southern part of the distribution post-glacially, leaving behind the rare alleles.

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