scholarly journals Simulation of pattern of gene flow in Canjerana fragments in the Brazilian Atlantic Rainforest for evaluating genetic conservation strategies

2019 ◽  
Vol 49 (8) ◽  
Author(s):  
Caetano Miguel Lemos Serrote ◽  
Lia Rejane Silveira Reiniger ◽  
Leonardo Severo da Costa ◽  
Charlene Moro Stefanel ◽  
Karol Buuron da Silva ◽  
...  
Keyword(s):  
Gene Flow ◽  
Isolation By Distance ◽  
Atlantic Rainforest ◽  
Conservation Strategies ◽  
Forest Fragments ◽  
Isolated Populations ◽  
Migration Rates ◽  
Distance Model ◽  
Priority Populations ◽  
Brazilian Atlantic Rainforest

ABSTRACT: Gene flow is important for the conservation of genetic resources to allow connectivity of geographically isolated populations and which genetic variability is reduced. Gene movement is a function of flow rate and model. Understanding how gene flow occurs can contribute to the conservation and selection of priority populations that could benefit from an eventual intervention. Simulation softwares allow making inferences about past events based on current datasets or predict future phenomena under real genetic scenarios. Adverse phenomena can be predicted and actions can be taken to avoid them. The aim of this study was to identify a model and the gene flow rates that could explain genetic structure of eight forest fragments of Cabralea canjerana in development in the Brazilian Atlantic Rainforest. To do this, simulations were performed with the EASYPOP software using a microsatellite marker dataset obtained for the species by Melo and collaborators, in 2012, 2014 and 2016. We tested five models and nine migration rates and we selected the model that produced values closer to those previously obtained for them. Criteria used for selection were the observed and expected heterozygosity and the Wright’s F Statistics obtained in the simulations. The gene flow model selected was the isolation by distance model that used a rate of 0.1. We observed high levels of genetic differentiation among the fragments as result of their reproductive isolation. To allow homogenization of the allelic frequencies through gene flow, the solution would be to create ecological corridors with the aim of connecting distant fragments.

scholarly journals Isolation and endemism in subterranean aquatic snails: unexpected case of Montenegrospeum bogici (Pešić et Glöer, 2012) (Gastropoda: Truncatelloidea: Hydrobiidae)

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Andrzej Falniowski ◽  
Vladimir Pešić ◽  
Brian Lewarne ◽  
Jozef Grego ◽  
Aleksandra Rysiewska ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Isolation By Distance ◽  
Karst Region ◽  
Aquatic Species ◽  
Isolated Populations ◽  
Dinaric Karst ◽  
Distance Model ◽  
Single Locality

AbstractThe subterranean aquatic snails may serve as a model of endemism and isolation vs. migration in subterranean habitats. The aim of the present paper is to verify the hypothesis that subterranean aquatic snails can migrate through diverse subterranean habitats, applying four molecular markers as well as a RAPD technique and shell morphometry. They were used to estimate the differences and gene flow between populations of the hydrobiid subterranean aquatic species Montenegrospeum bogici, collected in the Dinaric karst region. Three molecularly distinct taxonomic units were distinguished. The mOTU B was found at single locality, mOTU C at two, but the mOTU A at ten localities, scattered along 236 km distance, at two of them in sympatry with either mOTU B or C. Within mOTU A, the estimated levels of the gene flow were high. The pairwise measures of genetic differentiation were statistically significantly associated with geographic distances between the populations. In general, neither the infinite-island model of interpopulation differentiation, expected for isolated populations, nor the stepping-stone one, but rather the isolation-by-distance model explained the observed pattern. Our results suggest that interstitial habitats provide ways of migration for the stygobiont M. bogici, as has been already suggested for other subterranean gastropods.

Allozyme Evidence of Genetic Differentiation Between Populations of Hediste Diversicolor (Polychaeta: Nereididae) from the Western Mediterranean

1996 ◽  
Vol 76 (3) ◽  
pp. 637-647 ◽  
Author(s):  
M. Abbiati ◽  
F. Maltagliati
Keyword(s):  
Genetic Differentiation ◽  
Isolation By Distance ◽  
Western Mediterranean ◽  
Allozyme Electrophoresis ◽  
Isolated Populations ◽  
Hediste Diversicolor ◽  
Dispersal Capacity ◽  
Two Samples ◽  
Distance Model ◽  
Limited Dispersal

The occurrence of genetic differentiation among western Mediterranean Hediste diversicolor (Polychaeta: Nereididae) populations was assessed by allozyme electrophoresis on cellulose acetate. Seventeen loci were analysed in four populations. The level of the genetic variability was markedly low (mean HL range: 0.014–0.034), but comparable to that of other brackish water nereidids. The values of Nei genetic distance index (D) confirm the existence of genetic differentiation between the geographically isolated populations at Venice, Elba, Navicelli and Serchio D range: 0.128–0.356). However, the two samples from Serchio and Navicelli, ~15 km apart, were not genetically different (D=0·00005). The level of genetic differentiation in H. diversicolor populations followed the isolation-by-distance model. Reduced gene flow among H. diversicolor populations may be explained by its limited dispersal capacity and the eco-physiological barriers that occur between different brackish habitats.

Isonymy and population structure of Irish isolates during the 1890s

1982 ◽  
Vol 14 (2) ◽  
pp. 241-247 ◽  
Author(s):  
John H. Relethford
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Isolation By Distance ◽  
Breeding Population ◽  
Isolated Populations ◽  
Estimated Parameters ◽  
Distance Model ◽  
Local Breeding ◽  
And Migration ◽  
Close Fit

SummaryThe estimation of genetic similarity from correspondence of surnames (isonymy) allows investigation of historical population structure. This study uses surname data from seven isolates located along the west coast of Ireland during the 1890s to assess geographic and historic influences on population structure. Observed genetic variation among populations shows a close fit with the expected isolation by distance model, with estimated parameters of isolation and migration being similar to those obtained in other studies of isolated populations. Local genetic variation appears to be due primarily to the size of the local breeding population, with deviations being explained in terms of recent emigration.

scholarly journals Visualizing spatial population structure with estimated effective migration surfaces

2014 ◽  
Author(s):  
Desislava Petkova ◽  
John Novembre ◽  
Matthew Stephens
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Genetic Similarity ◽  
Large Scale ◽  
Genetic Model ◽  
Isolation By Distance ◽  
Genetic Data ◽  
Migration Rates ◽  
Spatial Population ◽  
Spatial Population Structure

Genetic data often exhibit patterns that are broadly consistent with "isolation by distance" - a phenomenon where genetic similarity tends to decay with geographic distance. In a heterogeneous habitat, decay may occur more quickly in some regions than others: for example, barriers to gene flow can accelerate the genetic differentiation between groups located close in space. We use the concept of "effective migration" to model the relationship between genetics and geography: in this paradigm, effective migration is low in regions where genetic similarity decays quickly. We present a method to quantify and visualize variation in effective migration across the habitat, which can be used to identify potential barriers to gene flow, from geographically indexed large-scale genetic data. Our approach uses a population genetic model to relate underlying migration rates to expected pairwise genetic dissimilarities, and estimates migration rates by matching these expectations to the observed dissimilarities. We illustrate the potential and limitations of our method using simulations and data from elephant, human, and Arabidopsis thaliana populations. The resulting visualizations highlight important features of the spatial population structure that are difficult to discern using existing methods for summarizing genetic variation such as principal components analysis.

scholarly journals Can secondary contact following range expansion be distinguished from barriers to gene flow?

2016 ◽  
Author(s):  
Johanna Bertl ◽  
Harald Ringbauer ◽  
Michael G. B. Blum
Keyword(s):  
Gene Flow ◽  
Range Expansion ◽  
Isolation By Distance ◽  
Molecular Data ◽  
Secondary Contact ◽  
Evolutionary Scenario ◽  
Coalescent Simulations ◽  
Distance Model ◽  
Northward Expansion ◽  
Spatio Temporal

AbstractSecondary contact is the reestablishment of gene flow between sister populations that have diverged. For instance, at the end of the Quaternary glaciations in Europe, secondary contact occurred during the northward expansion of the populations which had found refugia in the southern peninsulas. With the advent of multi-locus markers, secondary contact can be investigated using various molecular signatures including gradients of allele frequency, admixture clines, and local increase of genetic differentiation. We use coalescent simulations to investigate if molecular data provide enough information to distinguish between secondary contact following range expansion and an alternative evolutionary scenario consisting of a barrier to gene flow in an isolation-by-distance model. We find that an excess of Linkage Disequilibrium and of genetic diversity at the suture zone is a unique signature of secondary contact. We also find that the directionality index Ψ, which was proposed to study range expansion, is informative to distinguish between the two hypotheses. However, although evidence for secondary contact is usually conveyed by statistics related to admixture coefficients, we find that they can be confounded by isolation-by-distance. We recommend to account for the spatial repartition of individuals when investigating secondary contact in order to better reflect the complex spatio-temporal evolution of populations and species.

scholarly journals Nest and egg description of threatened Herpsilochmus spp. from coastal forest habitats in Rio Grande do Norte, Brazil (Aves: Thamnophilidae)

2008 ◽  
Vol 25 (3) ◽  
pp. 570-572 ◽  
Author(s):  
Marcelo da Silva ◽  
Mauro Pichorim ◽  
Márcio Z. Cardoso
Keyword(s):  
Atlantic Rainforest ◽  
Forest Fragments ◽  
Coastal Forest ◽  
Range Limit ◽  
Nest Structure ◽  
Open Forest ◽  
Northern Range Limit ◽  
Forest Habitats ◽  
Brazilian Atlantic Rainforest ◽  
Near Threatened

We provide description of eggs and nest structure for two Brazilian antwrens, including the IUCN "vulnerable" species, H. pectoralis Sclater, 1857, and the BirdLife International "near-threatened", H. sellowi Whitney & Pacheco, 2000. Our observations derive from a larger study on Herpsilochmus Cabanis, 1847 distribution in coastal forest fragments in the northern range limit of the Brazilian Atlantic rainforest. Both species nested in relatively open forest. The nest of H. sellowi was built with fungal hyphae, a trait common among some birds. Both eggs were moderately beige with brown spots. Most of the information on Brazilian antwren nesting comes from species that do not occur in the Atlantic rainforest. This is the first account for nest behavior for Atlantic rainforest antwrens.

scholarly journals A high gene flow in populations of Amblyomma ovale ticks found in distinct fragments of Brazilian Atlantic rainforest

2019 ◽  
Vol 77 (2) ◽  
pp. 215-228
Author(s):  
Gislene F. S. R. Fournier ◽  
Adriano Pinter ◽  
Renata Santiago ◽  
Sebastian Muñoz-Leal ◽  
Thiago Fernandes Martins ◽  
...  
Keyword(s):  
Gene Flow ◽  
Atlantic Rainforest ◽  
Amblyomma Ovale ◽  
High Gene Flow ◽  
High Gene ◽  
Brazilian Atlantic Rainforest

scholarly journals GENETIC DIVERSITY STUDIES OF LATVIAN VACCINIUM MYRTILLUS L. POPULATIONS FOR IN SITU CONSERVATION

AGROFOR ◽  
2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Agnese GAILĪTE ◽  
Anita GAILE ◽  
Dainis RUŅĢIS
Keyword(s):  
Genetic Diversity ◽  
Isolation By Distance ◽  
In Situ Conservation ◽  
Crop Wild Relatives ◽  
Vaccinium Myrtillus ◽  
Conservation Strategies ◽  
Forest Types ◽  
Isolated Populations ◽  
Vaccinium Myrtillus L

Plants and berries of bilberries (Vaccinium myrtillus L.) are traditionally used in many nations as a local medicine as well as edible plants. They are an important feed source for wild animals and birds. In situ conservation is an important component for the conservation of crop wild relatives (CWR) and wild harvested plants (WHP). Research on population structure and genetic diversity is important and is required for the development and implementation of in situ conservation strategies as well as being useful for ecosystem services management. The aim of this study was to test EST-SSR markers for bilberry genotyping and determine genetic diversity in different forest types – Vacciniosa, Myrtillosa, Hylocomiosa as well as compare populations from various regions of Latvia. Our results indicated that there was a small genetic differentiation between bilberries grown in different forest types (0-2%); most of the variation was found within individuals. Analysing populations in different regions of Latvia, 5% of the genetic variation was found among populations. Analysis using the STRUCTURE software package showed that there were no isolated populations or distinct groups. There was a positive correlation between geographic and genetic distances, indicating that the analysed populations differentiation can be explained by isolation-by-distance, without additional dispersal barriers.

scholarly journals The impact of edge effect on termite community (Blattodea: Isoptera) in fragments of Brazilian Atlantic Rainforest

2016 ◽  
Vol 77 (3) ◽  
pp. 519-526 ◽  
Author(s):  
C. S. Almeida ◽  
P. F. Cristaldo ◽  
D. F. Florencio ◽  
E. J. M. Ribeiro ◽  
N. G. Cruz ◽  
...  
Keyword(s):  
Edge Effect ◽  
Species Turnover ◽  
Forest Edge ◽  
Atlantic Rainforest ◽  
Conservation Strategies ◽  
Litter Biomass ◽  
Β Diversity ◽  
The Impact ◽  
Brazilian Atlantic Rainforest ◽  
Selection Of

Abstract Habitat fragmentation is considered to be one of the biggest threats to tropical ecosystem functioning. In this region, termites perform an important ecological role as decomposers and ecosystem engineers. In the present study, we tested whether termite community is negatively affected by edge effects on three fragments of Brazilian Atlantic Rainforest. Termite abundance and vegetation structure were sampled in 10 transects (15 × 2 m), while termite richness, activity, and soil litter biomass were measured in 16 quadrants (5 × 2 m) at forest edge and interior of each fragment. Habitat structure (i.e. number of tree, diameter at breast height and soil litter biomass) did not differ between forest edge and interior of fragments. Termite richness, abundance and activity were not affected by edge effect. However, differences were observed in the β diversity between forest edge and interior as well as in the fragments sampled. The β diversity partitioning indicates that species turnover is the determinant process of termite community composition under edge effect. Our results suggest that conservation strategies should be based on the selection of several distinct sites instead of few rich sites (e.g. nesting).

scholarly journals Can secondary contact following range expansion be distinguished from barriers to gene flow?

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5325 ◽  
Author(s):  
Johanna Bertl ◽  
Harald Ringbauer ◽  
Michael G.B. Blum
Keyword(s):  
Gene Flow ◽  
Range Expansion ◽  
Isolation By Distance ◽  
Molecular Data ◽  
Secondary Contact ◽  
Evolutionary Scenario ◽  
Coalescent Simulations ◽  
Distance Model ◽  
Northward Expansion ◽  
Spatio Temporal

Secondary contact is the reestablishment of gene flow between sister populations that have diverged. For instance, at the end of the Quaternary glaciations in Europe, secondary contact occurred during the northward expansion of the populations which had found refugia in the southern peninsulas. With the advent of multi-locus markers, secondary contact can be investigated using various molecular signatures including gradients of allele frequency, admixture clines, and local increase of genetic differentiation. We use coalescent simulations to investigate if molecular data provide enough information to distinguish between secondary contact following range expansion and an alternative evolutionary scenario consisting of a barrier to gene flow in an isolation-by-distance model. We find that an excess of linkage disequilibrium and of genetic diversity at the suture zone is a unique signature of secondary contact. We also find that the directionality index ψ, which was proposed to study range expansion, is informative to distinguish between the two hypotheses. However, although evidence for secondary contact is usually conveyed by statistics related to admixture coefficients, we find that they can be confounded by isolation-by-distance. We recommend to account for the spatial repartition of individuals when investigating secondary contact in order to better reflect the complex spatio-temporal evolution of populations and species.

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