scholarly journals Anthropogenic disturbance drives dispersal syndromes, demography, and gene flow in spatially structured amphibian populations

2019 ◽  
Author(s):  
Hugo Cayuela ◽  
Aurélien Besnard ◽  
Julien Cote ◽  
Martin Laporte ◽  
Eric Bonnaire ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Common Garden ◽  
Structured Populations ◽  
Habitat Patch ◽  
Dispersal Syndromes ◽  
Spatially Structured Populations ◽  
Capture Recapture ◽  
Common Garden Experiments ◽  
Dispersal Evolution

AbstractThere is growing evidence that anthropogenic landscapes can strongly influence the evolution of dispersal, particularly through fragmentation, and may drive organisms into an evolutionary trap by suppressing dispersal. However, the influence on dispersal evolution of anthropogenic variation in habitat patch turnover has so far been largely overlooked. In this study, we examined how human-driven variation in patch persistence affects dispersal rates and distances, determines dispersal-related phenotypic specialization, and drives neutral genetic structure in spatially structured populations. We addressed this issue in an amphibian, Bombina variegata, using an integrative approach combining capture–recapture modeling, demographic simulation, common garden experiments, and population genetics. B. variegata reproduces in small ponds that occur either in habitat patches that are persistent (i.e. several decades or more), located in riverine environments with negligible human activity, or in patches that are highly temporary (i.e. a few years), created by logging operations in intensively harvested woodland. Our capture–recapture models revealed that natal and breeding dispersal rates and distances were drastically higher in spatially structured populations (SSPs) in logging environments than in riverine SSPs. Population simulations additionally showed that dispersal costs and benefits drive the fate of logging SSPs, which cannot persist without dispersal. The common garden experiments revealed that toadlets reared in laboratory conditions have morphological and behavioral specialization that depends on their habitat of origin. Toadlets from logging SSPs were found to have higher boldness and exploration propensity than those from riverine SSPs, indicating transgenerationally transmitted dispersal syndromes. We also found contrasting patterns of neutral genetic diversity and gene flow in riverine and logging SSPs, with genetic diversity and effective population size considerably higher in logging than in riverine SSPs. In parallel, intra-patch inbreeding and relatedness levels were lower in logging SSPs. Controlling for the effect of genetic drift and landscape connectivity, gene flow was found to be higher in logging than in riverine SSPs. Taken together, these results indicate that anthropogenic variation in habitat patch turnover may have an effect at least as important as landscape fragmentation on dispersal evolution and the long-term viability and genetic structure of wild populations.

Genetic diversity and conservation of the endemic tuco-tuco Ctenomys ibicuiensis (Rodentia: Ctenomyidae)

2020 ◽  
Author(s):  
Mayara Delagnelo Medeiros ◽  
Daniel Galiano ◽  
Bruno Busnello Kubiak ◽  
Paula Angélica Roratto ◽  
Thales Renato Ochotorena de Freitas
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Environmental Changes ◽  
Isolation By Distance ◽  
Conservation Status ◽  
Significant Risk ◽  
Structured Populations ◽  
Small Range ◽  
High Genetic Diversity ◽  
Landscape Modification

Abstract Endemic, small range species are susceptible to environmental changes and landscape modification. Understanding genetic diversity and distributional patterns is important for implementation of effective conservation measures. In this context, genetic diversity was evaluated to update the conservation status of an endemic tuco-tuco, Ctenomys ibicuiensis. Phylogeographic and population genetic analyses of mitochondrial DNA and microsatellite loci were carried out using 46 individuals sampled across the species’ distribution. Ctenomys ibicuiensis presented moderate to high genetic diversity and highly structured populations with low levels of gene flow and isolation by distance. Anthropogenic landscape changes threaten this restricted-range tuco-tuco. Considering its limited geographic distribution and highly structured populations with low gene flow, we consider C. ibicuiensis to be at significant risk of extinction.

New insights into the polyploid complex Cenchrus ciliaris L. (Poaceae) show its capacity for gene flow and recombination processes despite its apomictic nature

2011 ◽  
Vol 59 (6) ◽  
pp. 543 ◽  
Author(s):  
Amina Kharrat-Souissi ◽  
Alex Baumel ◽  
Franck Torre ◽  
Marianick Juin ◽  
Sonja Siljak-Yakovlev ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Perennial Grass ◽  
Common Garden ◽  
Aflp Markers ◽  
Phenotypic Traits ◽  
Cenchrus Ciliaris ◽  
Ploidy Levels ◽  
Recombination Processes

Cenchrus ciliaris L. is a C4 perennial grass of arid lands which is under the focus of different ecological issues such as response to desertification, quality of forage grass and impacts of invasions. Here, molecular and morphological analyses of the genetic diversity of several Tunisian provenances of C. ciliaris were performed to better understand the phenotypic polymorphism of this agamospermous and polyploid grass. Ten phenotypic traits associated with productivity were measured in a common garden environment. Amplified Fragment Length Polymorphism (AFLP) markers were developed to investigate the structure of genetic diversity among and within provenances and between the three ploidy levels. Heritable phenotypic traits showed considerable differences within provenances. Surprisingly, AFLP markers revealed the existence of genotypic variations between individuals of the same sibship and a high G/N value (0.55). A neighbour-joining tree based on AFLP markers revealed three major groups; tetraploid, pentaploid and a mix of pentaploid and hexaploids. These groups do not correspond completely to the geographical origin of samples. The results underline the possibility of sexual reproduction, recombination and gene flow within and between populations of C. ciliaris. In respect with the well known dynamic nature of polyploid genomes, these results should have strong consequences for the future management of this grass for both conservation and invasion issues.

scholarly journals Annual aboveground carbon uptake enhancements from assisted gene flow in boreal black spruce forests are not long-lasting

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Martin P. Girardin ◽  
Nathalie Isabel ◽  
Xiao Jing Guo ◽  
Manuel Lamothe ◽  
Isabelle Duchesne ◽  
...  
Keyword(s):  
Gene Flow ◽  
Net Primary Productivity ◽  
Black Spruce ◽  
Carbon Sink ◽  
Phenotypic Variability ◽  
Common Garden ◽  
Phylogeographic Structure ◽  
Aboveground Net Primary Productivity ◽  
Common Garden Experiments ◽  
Positive Effect

AbstractAssisted gene flow between populations has been proposed as an adaptive forest management strategy that could contribute to the sequestration of carbon. Here we provide an assessment of the mitigation potential of assisted gene flow in 46 populations of the widespread boreal conifer Picea mariana, grown in two 42-year-old common garden experiments and established in contrasting Canadian boreal regions. We use a dendroecological approach taking into account phylogeographic structure to retrospectively analyse population phenotypic variability in annual aboveground net primary productivity (NPP). We compare population NPP phenotypes to detect signals of adaptive variation and/or the presence of phenotypic clines across tree lifespans, and assess genotype‐by‐environment interactions by evaluating climate and NPP relationships. Our results show a positive effect of assisted gene flow for a period of approximately 15 years following planting, after which there was little to no effect. Although not long lasting, well-informed assisted gene flow could accelerate the transition from carbon source to carbon sink after disturbance.

scholarly journals Consequences of gene flow in spatially structured populations

1997 ◽  
Vol 69 (1) ◽  
pp. 49-60 ◽  
Author(s):  
KATRINA A. LYTHGOE
Keyword(s):  
Gene Flow ◽  
Simple Model ◽  
Migration Rate ◽  
Genetic Variance ◽  
Structured Populations ◽  
Stabilizing Selection ◽  
Heritable Variation ◽  
Fluctuating Selection ◽  
Spatially Structured Populations ◽  
Two Populations

A simple model of migration between two populations, each in a balance between mutation and stabilizing selection on a polygenic trait, is explored. Below a critical migration rate, genetic differences between the two populations can be maintained, even if the populations are selected towards the same phenotypic optimum. Gene flow then maintains genetic variance within each population. For this process to account for heritable variation, there must be some mechanism that causes divergence. The possibility that fluctuating selection could lead to the initial differentiation of the populations is explored.

scholarly journals Fragmentation helps evolutionary rescue in highly connected habitats

2020 ◽  
Author(s):  
Matteo Tomasini ◽  
Stephan Peischl
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Environmental Conditions ◽  
Structured Populations ◽  
Adaptive Introgression ◽  
Spatially Structured Populations ◽  
Species Survival ◽  
Evolutionary Rescue ◽  
The Face ◽  
Population Sizes

AbstractGenetic variation and population sizes are critical factors for successful adaptation to novel environmental conditions. Gene flow between sub-populations is a potent mechanism to provide such variation and can hence facilitate adaption, for instance by increasing genetic variation or via adaptive introgression. On the other hand, if gene flow between different habitats is too strong, locally beneficial alleles may not be able to establish permanently. In the context of evolutionary rescue, intermediate levels of gene flow are therefore often optimal for maximizing a species chance for survival in meta-populations without spatial structure. To which extent and under which conditions gene flow facilitates or hinders evolutionary rescue in spatially structured populations remains unresolved. We address this question and show that detrimental effects of gene flow can become negligible in spatially structured populations subject to a gradual deterioration of environmental conditions. If the number of sub-populations is sufficiently large, we find a positive relationship between the amount of gene flow and the survival chance of the population. A counter-intuitive conclusion is that increased fragmentation can facilitate species survival in the face of severe environmental change if migration is common but limited to neighboring sub-populations.

Informed dispersal, heterogeneity in animal dispersal syndromes and the dynamics of spatially structured populations

2009 ◽  
Vol 12 (3) ◽  
pp. 197-209 ◽  
Author(s):  
Jean Clobert ◽  
Jean-François Le Galliard ◽  
Julien Cote ◽  
Sandrine Meylan ◽  
Manuel Massot
Keyword(s):  
Structured Populations ◽  
Dispersal Syndromes ◽  
Spatially Structured Populations ◽  
Informed Dispersal

Genealogies and geography

1995 ◽  
Vol 349 (1327) ◽  
pp. 49-59 ◽  
Keyword(s):  
Gene Flow ◽  
Geographic Location ◽  
Close Relation ◽  
Structured Populations ◽  
Population Genetic Analysis ◽  
Simple Diffusion ◽  
Spatially Structured Populations ◽  
Classic Theory ◽  
History Of

Any sample of genes traces back to a single common ancestor. Each gene also has other properties: its sequence, its geographic location and the phenotype and fitness of the organism that carries it. With sexual reproduction, different genes have different genealogies, which gives us much more information, but also greatly complicates population genetic analysis. We review the close relation between the distribution of genealogies and the classic theory of identity by descent in spatially structured populations, and develop a simple diffusion approximation to the distribution of coalescence times in a homogeneous two-dimensional habitat. This shows that when neighbourhood size is large (as in most populations) only a small fraction of pairs of genes are closely related, and only this fraction gives information about current rates of gene flow. The increase of spatial dispersion with lineage age is thus a poor estimator of gene flow. The bulk of the genealogy depends on the long-term history of the population; we discuss ways of inferring this history from the concordance between genealogies across loci.

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.

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