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

2010 ◽  
Vol 7 (1) ◽  
pp. 37-48 ◽  
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

scholarly journals Genomic variation in the American pika: signatures of geographic isolation and implications for conservation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kelly B. Klingler ◽  
Joshua P. Jahner ◽  
Thomas L. Parchman ◽  
Chris Ray ◽  
Mary M. Peacock
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Sierra Nevada ◽  
Spatial Genetic Structure ◽  
Spatial Scales ◽  
Thermal Sensitivity ◽  
Genomic Variation ◽  
Genome Wide ◽  
A Genome ◽  
American Pika

Abstract Background Distributional responses by alpine taxa to repeated, glacial-interglacial cycles throughout the last two million years have significantly influenced the spatial genetic structure of populations. These effects have been exacerbated for the American pika (Ochotona princeps), a small alpine lagomorph constrained by thermal sensitivity and a limited dispersal capacity. As a species of conservation concern, long-term lack of gene flow has important consequences for landscape genetic structure and levels of diversity within populations. Here, we use reduced representation sequencing (ddRADseq) to provide a genome-wide perspective on patterns of genetic variation across pika populations representing distinct subspecies. To investigate how landscape and environmental features shape genetic variation, we collected genetic samples from distinct geographic regions as well as across finer spatial scales in two geographically proximate mountain ranges of eastern Nevada. Results Our genome-wide analyses corroborate range-wide, mitochondrial subspecific designations and reveal pronounced fine-scale population structure between the Ruby Mountains and East Humboldt Range of eastern Nevada. Populations in Nevada were characterized by low genetic diversity (π = 0.0006–0.0009; θW = 0.0005–0.0007) relative to populations in California (π = 0.0014–0.0019; θW = 0.0011–0.0017) and the Rocky Mountains (π = 0.0025–0.0027; θW = 0.0021–0.0024), indicating substantial genetic drift in these isolated populations. Tajima’s D was positive for all sites (D = 0.240–0.811), consistent with recent contraction in population sizes range-wide. Conclusions Substantial influences of geography, elevation and climate variables on genetic differentiation were also detected and may interact with the regional effects of anthropogenic climate change to force the loss of unique genetic lineages through continued population extirpations in the Great Basin and Sierra Nevada.

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

Heredity ◽  
2008 ◽  
Vol 102 (3) ◽  
pp. 274-285 ◽  
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

scholarly journals Isolation by resistance across a complex coral reef seascape

2015 ◽  
Vol 282 (1812) ◽  
pp. 20151217 ◽  
Author(s):  
Luke Thomas ◽  
W. Jason Kennington ◽  
Michael Stat ◽  
Shaun P. Wilkinson ◽  
Johnathan T. Kool ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Divergence ◽  
Larval Dispersal ◽  
Population Genetic ◽  
Spatial Genetic Structure ◽  
Spatial Scales ◽  
Genetic Data ◽  
Genetic Structure Of Populations ◽  
Seascape Genetics

A detailed understanding of the genetic structure of populations and an accurate interpretation of processes driving contemporary patterns of gene flow are fundamental to successful spatial conservation management. The field of seascape genetics seeks to incorporate environmental variables and processes into analyses of population genetic data to improve our understanding of forces driving genetic divergence in the marine environment. Information about barriers to gene flow (such as ocean currents) is used to define a resistance surface to predict the spatial genetic structure of populations and explain deviations from the widely applied isolation-by-distance model. The majority of seascape approaches to date have been applied to linear coastal systems or at large spatial scales (more than 250 km), with very few applied to complex systems at regional spatial scales (less than 100 km). Here, we apply a seascape genetics approach to a peripheral population of the broadcast-spawning coral Acropora spicifera across the Houtman Abrolhos Islands, a high-latitude complex coral reef system off the central coast of Western Australia. We coupled population genetic data from a panel of microsatellite DNA markers with a biophysical dispersal model to test whether oceanographic processes could explain patterns of genetic divergence. We identified significant variation in allele frequencies over distances of less than 10 km, with significant differentiation occurring between adjacent sites but not between the most geographically distant ones. Recruitment probabilities between sites based on simulated larval dispersal were projected into a measure of resistance to connectivity that was significantly correlated with patterns of genetic divergence, demonstrating that patterns of spatial genetic structure are a function of restrictions to gene flow imposed by oceanographic currents. This study advances our understanding of the role of larval dispersal on the fine-scale genetic structure of coral populations across a complex island system and applies a methodological framework that can be tailored to suit a variety of marine organisms with a range of life-history characteristics.

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

2002 ◽  
Vol 79 (3) ◽  
pp. 219-226 ◽  
Author(s):  
GUDRUN P. WELLS ◽  
ANDREW G. YOUNG
Keyword(s):  
Genetic Structure ◽  
Seed Dispersal ◽  
Genetic Relatedness ◽  
Spatial Genetic Structure ◽  
Dispersal Distance ◽  
Self Incompatibility ◽  
Southeastern Australia ◽  
Incompatibility System ◽  
Significant Patterns ◽  
Different Levels

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.

scholarly journals Genomic variation in the American pika: signatures of geographic isolation and implications for conservation

2020 ◽  
Author(s):  
Kelly Brie Klingler ◽  
Joshua P Jahner ◽  
Thomas L Parchman ◽  
Chris Ray ◽  
Mary Peacock
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Sierra Nevada ◽  
Spatial Genetic Structure ◽  
Spatial Scales ◽  
Thermal Sensitivity ◽  
Genomic Variation ◽  
Genome Wide ◽  
A Genome ◽  
American Pika

Abstract Background: Distributional responses by alpine taxa to repeated, glacial-interglacial cycles throughout the last two million years have significantly influenced the spatial genetic structure of populations. These effects have been exacerbated for the American pika (Ochotona princeps), a small alpine lagomorph constrained by thermal sensitivity and a limited dispersal capacity. As a species of conservation concern, long-term lack of gene flow has important consequences for landscape genetic structure and levels of diversity within populations. Here, we use reduced representation sequencing (ddRADseq) to provide a genome-wide perspective on patterns of genetic variation across pika populations representing distinct subspecies. To investigate how landscape and environmental features shape genetic variation, we collected genetic samples from distinct geographic regions as well as across finer spatial scales in two geographically proximate mountain ranges of eastern Nevada. Results: Our genome-wide analyses corroborate range-wide, mitochondrial subspecific designations and reveal pronounced fine-scale population structure between the Ruby Mountains and East Humboldt Range of eastern Nevada. Populations in Nevada were characterized by low genetic diversity (𝜋=0.0006–0.0009; 𝜃W=0.0005–0.0007) relative to populations in California (𝜋=0.0014–0.0019; 𝜃W=0.0011–0.0017) and the Rocky Mountains (𝜋=0.0025–0.0027; 𝜃W=0.0021–0.0024), indicating substantial genetic drift in these isolated populations. Tajima’s D was positive for all sites (D=0.240-0.811), consistent with recent contraction in population sizes range-wide. Conclusions: Substantial influences of geography, elevation and climate variables on genetic differentiation were also detected and may interact with the regional effects of anthropogenic climate change to force the loss of unique genetic lineages through continued population extirpations in the Great Basin and Sierra Nevada.

Analysis of the spatial genetic structure of Passiflora incarnata in recently disturbed sites

2005 ◽  
Vol 83 (4) ◽  
pp. 420-426 ◽  
Author(s):  
Rebecca T Tague ◽  
Stephanie A Foré
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Spatial Genetic Structure ◽  
Spatial Scales ◽  
Multilocus Genotype ◽  
Long Distance ◽  
Short Life Span ◽  
Successional Species ◽  
Passiflora Incarnata ◽  
Coefficient Of Coancestry

In early successional species, short life span and frequent spatial relocation may affect the distribution of genetic variation but the pattern may be altered by reproductive patterns. Passiflora incarnata L. (Passifloraceae), an early successional vine found throughout the southeastern United States, reproduces sexually and asexually through clonal sprouts. We examined the genetic structure of P. incarnata in recently disturbed habitats at three spatial scales: within a patch, among patches separated by 250 m, and between sites separated by 10 km. Genetic variation may be clumped at the scale of neighboring plants if stem resprouting is significant. In each patch, eleven arbitrarily selected plants and their four nearest neighbors were mapped and leaf samples were collected for genetic analysis. The multilocus genotype of each individual for seven polymorphic allozymes was determined. Potential clones were determined by estimating the probability of a second occurrence of each genotype and a multilocus coefficient of coancestry. Data indicated P. incarnata was reproducing primarily sexually. Most of the genetic variation was within a patch with little variation among patches. These data suggest that the genetic structure of this colonizing species was determined by founder effects interacting with long distance pollen movement.Key words: allozymes, passionflower, spatial, genetic structure, early colonizer, Passiflora incarnata.

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

2016 ◽  
Vol 65 (2) ◽  
pp. 46-57 ◽  
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.

Spatial genetic structure of lowbush blueberry, Vaccinium angustifolium, in four fields in Maine

Botany ◽  
2009 ◽  
Vol 87 (10) ◽  
pp. 932-946 ◽  
Author(s):  
Daniel J. Bell ◽  
Lisa J. Rowland ◽  
Dapeng Zhang ◽  
Frank A. Drummond
Keyword(s):  
Genetic Structure ◽  
Genetic Similarity ◽  
Seedling Recruitment ◽  
Expressed Sequence Tag ◽  
Spatial Genetic Structure ◽  
Spatial Scales ◽  
Principal Component ◽  
Physical Distance ◽  
Vaccinium Angustifolium ◽  
Lowbush Blueberry

Expressed sequence tag – polymerase chain reaction (EST-PCR) molecular markers were used to infer spatial genetic structure of four lowbush blueberry ( Vaccinium angustifolium Ait.) fields in Maine. Genetic structure was quantified at three spatial scales: (1) within apparent clones (intrapatch), (2) among clones within a field, and (3) among fields separated by as much as 65 km. Of five “clones” or putative individuals examined in the intrapatch study, two showed complete genetic homogeneity within the patch, while three showed some band differences at their edges compared with their interiors. These differences at the edges, however, matched adjacent clones (so-called “intruders”), from which it was concluded that lowbush blueberry exhibits a fairly tight, phalanx clonal architecture with no evidence of invasive seedling establishment within clones. No significant correlation between genetic and physical distance was found among clones within fields via several statistical approaches. Significant among-field genetic differentiation was found via AMOVA (ΦPT = 8.4%; p ≤ 0.01) based upon transect samples across four fields ranging from 12.5 to 65 km apart. Principal component analysis and spatial autocorrelation (SA) corroborated these findings. Significant positive SA was found at the within-field distance class of <350 m, but SA decreased to an insignificant value by the first interfield distance of 12.5 km. A special form of SA analysis was employed to detect “hotspots” of genetic similarity between pairs of adjacent clones in two fields. Results indicated that 5 of 23 pairs of clones (21.7%) were genetically similar to each other, while the majority of pairs (18 of 23; 78.3%) showed random, decreasing patterns of genetic similarity. Results are discussed in terms of clonal dynamics including architecture, seedling recruitment, and inferred pollen or seed dispersal distances.

scholarly journals Landscape-Level and Fine-Scale Genetic Structure of the Neotropical TreeProtium spruceanum(Burseraceae)

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Fábio de Almeida Vieira ◽  
Cristiane Gouvêa Fajardo ◽  
Anderson Marcos de Souza ◽  
Dulcinéia de Carvalho
Keyword(s):  
Genetic Structure ◽  
Spatial Genetic Structure ◽  
Spatial Scales ◽  
Conservation Strategies ◽  
Forest Fragments ◽  
Fine Scale ◽  
Conservation Units ◽  
Significant Genetic Structure ◽  
Protium Spruceanum ◽  
Allozyme Loci

Knowledge of genetic structure at different scales and correlation with the current landscape is fundamental for evaluating the importance of evolutionary processes and identifying conservation units. Here, we used allozyme loci to examine the spatial genetic structure (SGS) of 230 individuals ofProtium spruceanum, a native canopy-emergent in five fragments of Brazilian Atlantic forest (1 to 11.8 ha), and four ecological corridors (460 to 1 000 m length). Wright's statistic and Mantel tests revealed little evidence of significant genetic structure at the landscape-scale (; , ). At fine-scale SGS, low levels of relatedness within fragments and corridors (, ) were observed. Differences in the levels and distribution of the SGS at both spatial scales are discussed in relation to biological and conservation strategies of corridors and forest fragments.

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