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.

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.

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 Application of a random walk model to geographic distributions of animal mitochondrial DNA variation.

Genetics ◽  
1993 ◽  
Vol 135 (4) ◽  
pp. 1209-1220 ◽  
Author(s):  
J E Neigel ◽  
J C Avise
Keyword(s):  
Mitochondrial Dna ◽  
Isolation By Distance ◽  
Natural Populations ◽  
Data Sets ◽  
Long Distance ◽  
Dna Variation ◽  
Distance Model ◽  
Limited Dispersal ◽  
Geographic Distributions ◽  
Lineage Structure

Abstract In rapidly evolving molecules, such as animal mitochondrial DNA, mutations that delineate specific lineages may not be dispersed at sufficient rates to attain an equilibrium between genetic drift and gene flow. Here we predict conditions that lead to nonequilibrium geographic distributions of mtDNA lineages, test the robustness of these predictions and examine mtDNA data sets for consistency with our model. Under a simple isolation by distance model, the variance of an mtDNA lineage's geographic distribution is expected be proportional to its age. Simulation results indicated that this relationship is fairly robust. Analysis of mtDNA data from natural populations revealed three qualitative distributional patterns: (1) significant departure of lineage structure from equilibrium geographic distributions, a pattern exhibited in three rodent species with limited dispersal; (2) nonsignificant departure from equilibrium expectations, exhibited by two avian and two marine fish species with potentials for relatively long-distance dispersal; and (3) a progression from nonequilibrium distributions for younger lineages to equilibrium distributions for older lineages, a condition displayed by one surveyed avian species. These results demonstrate the advantages of considering mutation and genealogy in the interpretation of mtDNA geographic variation.

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 Highly restricted dispersal in habitat-forming seaweed may impede natural recovery of disturbed populations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Florentine Riquet ◽  
Christiane-Arnilda De Kuyper ◽  
Cécile Fauvelot ◽  
Laura Airoldi ◽  
Serge Planes ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Spatial Scales ◽  
Mediterranean Ecosystems ◽  
Dispersal Distance ◽  
Genetic Connectivity ◽  
Restricted Gene Flow ◽  
Isolated Populations ◽  
Natural Recovery ◽  
Limited Dispersal ◽  
Ecological Importance

AbstractCystoseira sensu lato (Class Phaeophyceae, Order Fucales, Family Sargassaceae) forests play a central role in marine Mediterranean ecosystems. Over the last decades, Cystoseira s.l. suffered from a severe loss as a result of multiple anthropogenic stressors. In particular, Gongolaria barbata has faced multiple human-induced threats, and, despite its ecological importance in structuring rocky communities and hosting a large number of species, the natural recovery of G. barbata depleted populations is uncertain. Here, we used nine microsatellite loci specifically developed for G. barbata to assess the genetic diversity of this species and its genetic connectivity among fifteen sites located in the Ionian, the Adriatic and the Black Seas. In line with strong and significant heterozygosity deficiencies across loci, likely explained by Wahlund effect, high genetic structure was observed among the three seas (ENA corrected FST = 0.355, IC = [0.283, 0.440]), with an estimated dispersal distance per generation smaller than 600 m, both in the Adriatic and Black Sea. This strong genetic structure likely results from restricted gene flow driven by geographic distances and limited dispersal abilities, along with genetic drift within isolated populations. The presence of genetically disconnected populations at small spatial scales (< 10 km) has important implications for the identification of relevant conservation and management measures for G. barbata: each population should be considered as separated evolutionary units with dedicated conservation efforts.

scholarly journals Genetic differentiation in Scottish populations of the pine beauty moth, Panolis flammea (Lepidoptera: Noctuidae)

2005 ◽  
Vol 95 (6) ◽  
pp. 517-526 ◽  
Author(s):  
A.J. Lowe ◽  
B.J. Hicks ◽  
K. Worley ◽  
R.A. Ennos ◽  
J.D. Morman ◽  
...  
Keyword(s):  
Genetic Differentiation ◽  
Scots Pine ◽  
Rapd Analysis ◽  
Isolation By Distance ◽  
Long Distance ◽  
Panolis Flammea ◽  
Colonization Dynamics ◽  
Low Levels ◽  
Lepidoptera Noctuidae ◽  
Limited Exchange

AbstractPine beauty moth, Panolis flammea (Denis & Schiffermüller), is a recent but persistent pest of lodgepole pine plantations in Scotland, but exists naturally at low levels within remnants and plantations of Scots pine. To test whether separate host races occur in lodgepole and Scots pine stands and to examine colonization dynamics, allozyme, randomly amplified polymorphic DNA (RAPD) and mitochondrial variation were screened within a range of Scottish samples. RAPD analysis indicated limited long distance dispersal (FST = 0.099), and significant isolation by distance (P < 0.05); but that colonization between more proximate populations was often variable, from extensive to limited exchange. When compared with material from Germany, Scottish samples were found to be more diverse and significantly differentiated for all markers. For mtDNA, two highly divergent groups of haplotypes were evident, one group contained both German and Scottish samples and the other was predominantly Scottish. No genetic differentiation was evident between P. flammea populations sampled from different hosts, and no diversity bottleneck was observed in the lodgepole group. Indeed, lodgepole stands appear to have been colonized on multiple occasions from Scots pine sources and neighbouring populations on different hosts are close to panmixia.

Parnassius nebrodensis: A threatened but neglected Apollo butterfly species from Southern Europe (Lepidoptera: Papilionidae)

2021 ◽  
Vol 40 ◽  
pp. 140-163
Author(s):  
Ivan N. Bolotov ◽  
Mikhail Y. Gofarov ◽  
Vyacheslav V. Gorbach ◽  
Yulia S. Kolosova ◽  
Alisa A. Zheludkova ◽  
...  
Keyword(s):  
Population Decline ◽  
Western Mediterranean ◽  
Butterfly Species ◽  
Isolated Populations ◽  
Nucleotide Substitutions ◽  
Mitochondrial Coi ◽  
Mountain Ranges ◽  
Cryptic Species Complex ◽  
Phylogenetic Lineages ◽  
Apollo Butterfly

Recent multi-locus phylogenetic studies repeatedly showed that what was thought to be the Clouded Apollo butterfly Parnassius mnemosyne (Linnaeus, 1758) represents a cryptic species complex. This complex contains at least three distant species-level phylogenetic lineages. Here, we compile a set of morphology- and DNA-based evidences supporting the distinctiveness of two species in this group, i.e. P. mnemosyne s. str. and P. nebrodensis Turati, 1907 stat. rev. These species can be distinguished from each other based on a combination of diagnostic characters in the male genitalia structure, wing scale patterns, and the forewing venation. The species status of P. nebrodensis is supported based on unique nucleotide substitutions in the mitochondrial (COI, ND1, and ND5) and nuclear (Wg and EF-1a) genes. P. nebrodensis is endemic to the Western Mediterranean Region. This species shares a disjunctive range through the Pyrenees, Western and Central Alps, Apennines, and the Nebrodi and Madonie mountains on Sicily. Altogether 38 nominal taxa initially described as P. mnemosyne subspecies are considered here to be junior synonyms of P. nebrodensis. At first glance, P. nebrodensis can be assessed as an endangered species due to its restricted distribution, narrow range of habitats, and ongoing population decline. Isolated populations of this species scattered through mountain ranges need special management and conservation efforts.

scholarly journals Nonsignificant isolation by distance implies limited dispersal

2012 ◽  
Vol 21 (23) ◽  
pp. 5637-5639 ◽  
Author(s):  
Katie E. Lotterhos
Keyword(s):  
Isolation By Distance ◽  
Limited Dispersal

scholarly journals Population genetic structure of European wildcats inhabiting the area between the Dinaric Alps and the Scardo-Pindic mountains

2021 ◽  
Author(s):  
Felicita Urzi ◽  
Nikica Šprem ◽  
Hubert Potočnik ◽  
Magda Sindičić ◽  
Dean Konjević ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Population Genetic ◽  
Allelic Richness ◽  
Isolation By Distance ◽  
Domestic Cats ◽  
Genetic Purity ◽  
Eastern Group ◽  
Two Samples ◽  
European Wildcat ◽  
Genetic Clusters

Abstract Habitat fragmentation and loss have contributed significantly to the demographic decline of European wildcat populations and hybridization with domestic cats poses a threat to the loss of genetic purity of the species. In this study we used microsatellite markers to analyse genetic variation and structure of the wildcat populations from the area between the Dinaric Alps and the Scardo-Pindic mountains in Slovenia, Croatia, Serbia and North Macedonia. We also investigated hybridisation between populations of wildcats and domestic cats in the area. One hundred and thirteen samples from free-leaving European wildcats and thirty-two samples from domestic cats were analysed. Allelic richness across populations ranged from 3.61 to 3.98. The observed Ho values ranged between 0.57 and 0.71. The global FST value for the four populations was 0.080 (95% CI 0.056–0.109) and differed significantly from zero (P < 0.001). The highest FST value was observed between the populations North Macedonia and Slovenia and the lowest between Slovenia and Croatia. We also found a signal for the existence of isolation by distance between populations. Our results showed that wildcats are divided in two genetic clusters largely consistent with a geographic division into a genetically diverse northern group (Slovenia, Croatia) and genetically eroded south-eastern group (Serbia, N. Macedonia). Hybridisation rate between wildcats and domestic cats varied between 13% and 52% across the regions.

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