scholarly journals Population Genomics and Lagrangian Modeling Shed Light on Dispersal Events in the Mediterranean Endemic Ericaria zosteroides (=Cystoseira zosteroides) (Fucales)

2021 ◽  
Vol 8 ◽  
Author(s):  
Lauric Reynes ◽  
Didier Aurelle ◽  
Cristele Chevalier ◽  
Christel Pinazo ◽  
Myriam Valero ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Population Genomics ◽  
Spatial Scales ◽  
Seawater Temperature ◽  
Marine Species ◽  
Population Connectivity ◽  
Central Process ◽  
Lagrangian Modeling ◽  
Dispersal Events

Dispersal is a central process that affects population growth, gene flow, and ultimately species persistence. Here we investigate the extent to which gene flow occurs between fragmented populations of the deep-water brown algae Ericaria zosteroides (Turner) Greville (Sargassaceae, Fucales). These investigations were performed at different spatial scales from the bay of Marseille (western Provence) to Corsica. As dispersal of zygotes is shown to be limited over distances beyond a few meters, we used a multidisciplinary approach, based on Lagrangian modeling and population genomics to test the hypothesis that drifting of fertile parts of thallus (eggs on fertile branches), mediated by ocean currents, enable occasional gene flow between populations. Therefore we assessed the respective contribution of oceanographic connectivity, geographical isolation, and seawater temperatures to the genetic structure of this species. The genetic structure was assessed using 10,755 neutral SNPs and 12 outlier SNPs genotyped by dd-RAD sequencing in 261 individuals of E. zosteroides. We find that oceanographic connectivity is the best predictor of genetic structure, while differentiation in outlier SNPs can be explained by the depth of populations, as emphasized by the minimum seawater temperature predictor. However, further investigations will be necessary for clarifying how depth drives adaptive genetic differentiation in E. zosteroides. Our analyses revealed that local hydrodynamic conditions are correlated with the very high divergence of one population in the Bay of Marseille. Overall, the levels of gene flow mediated by drifting were certainly not sufficient to counteract differentiation by local genetic drift, but enough to allow colonization several kilometers away. This study stresses the need to consider secondary dispersal mechanisms of presumed low dispersal marine species to improve inference of population connectivity.

scholarly journals Stirred but not shaken: population and recruitment genetics of the scallop (Pecten fumatus) in Bass Strait, Australia

2016 ◽  
Vol 73 (9) ◽  
pp. 2333-2341 ◽  
Author(s):  
Jennifer R. Ovenden ◽  
Bree J. Tillett ◽  
Michael Macbeth ◽  
Damien Broderick ◽  
Fiona Filardo ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Allelic Variation ◽  
Open Water ◽  
Marine Species ◽  
Population Connectivity ◽  
Valuable Insight ◽  
Fine Scale ◽  
Scale Population

Abstract We report population genetic structure and fine-scale recruitment processes for the scallop beds (Pecten fumatus) in Bass Strait and the eastern coastline of Tasmania in southern Australia. Conventional population pairwise FST analyses are compared with novel discriminant analysis of principal components (DAPC) to assess population genetic structure using allelic variation in 11 microsatellite loci. Fine-scale population connectivity was compared with oceanic features of the sampled area. Disjunct scallop beds were genetically distinct, but there was little population genetic structure between beds connected by tides and oceanic currents. To identify recruitment patterns among and within beds, pedigree analyses determined the distribution of parent–offspring and sibling relationships in the sampled populations. Beds in northeastern Bass Strait were genetically distinct to adjacent beds (FST 0.003–0.005) and may not contribute to wider recruitment based on biophysical models of larval movement. Unfortunately, pedigree analyses lacked power to further dissect fine-scale recruitment processes including self-recruitment. Our results support the management of disjunct populations as separate stocks and the protection of source populations among open water beds. The application of DAPC and parentage analyses in the current study provided valuable insight into their potential power to determine population connectivity in marine species with larval 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 Population structure and dispersal across small and large spatial scales in a direct developing marine isopod

2020 ◽  
Author(s):  
William S. Pearman ◽  
Sarah J. Wells ◽  
Olin K. Silander ◽  
Nikki E. Freed ◽  
James Dale
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Population Genetic ◽  
Isolation By Distance ◽  
Spatial Scales ◽  
Population Connectivity ◽  
Clear Pattern ◽  
Small Spatial Scale ◽  
Cook Strait ◽  
Genetic Break

AbstractMarine organisms generally exhibit one of two developmental modes: biphasic, with distinct adult and larval morphology, and direct development, in which larvae resemble adults. Developmental mode is thought to significantly influence dispersal, with direct developers expected to have much lower dispersal potential. However, in contrast to our relatively good understanding of dispersal and population connectivity for biphasic species, comparatively little is known about direct developers. In this study, we use a panel of 8,020 SNPs to investigate population structure and gene flow for a direct developing species, the New Zealand endemic marine isopod Isocladus armatus. On a small spatial scale (20 kms), gene flow between locations is extremely high and suggests an island model of migration. However, over larger spatial scales (600km), populations exhibit a clear pattern of isolation-by-distance. Because our sampling range is intersected by two well-known biogeographic barriers (the East Cape and the Cook Strait), our study provides an opportunity to understand how such barriers influence dispersal in direct developers. Our results indicate that I. armatus exhibits significant migration across these barriers, and suggests that ocean currents associated with these locations do not present a barrier to dispersal. Interestingly, we do find evidence of a north-south population genetic break occurring between Māhia and Wellington, two locations where there are no obvious biogeographic barriers between them. We conclude that developmental life history largely predicts dispersal in intertidal marine isopods. However, localised biogeographic processes can disrupt this expectation.

Population genetic structure of Indo-West Pacific carcharhinid sharks: what do we know and where to from here?

2020 ◽  
Vol 26 (4) ◽  
pp. 319
Author(s):  
Brenton M. Pember ◽  
Jennifer A. Chaplin ◽  
Neil R. Loneragan ◽  
Matias Braccini
Keyword(s):  
Genetic Structure ◽  
Dna Sequences ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Population Genomics ◽  
Spatial Scales ◽  
Small Sample ◽  
Future Research ◽  
Individual Species ◽  
West Pacific

The Carcharhinidae is one of the most at-risk shark families in the Indo-West Pacific (IWP), which is a global priority for the conservation of elasmobranchs. Of the 57 described species of carcharhinids, 43 are known from the IWP, where many are subject to high fishing pressure. Many of these species are also found outside this bioregion. Understanding the connectivity of individual species across their ranges is paramount to successful management of their fisheries. Studies of population genetic structure have been the mainstay for assessing connectivity. Here, we review 41 studies pertaining to the population genetic structure of 20 species of carcharhinid whose ranges include the IWP and for which relevant data are available. The genetic markers used range from microsatellite loci and small mitochondrial DNA sequences (375 to 4797bp) to genomic analyses. Overall, the population genetic structure for these carcharhinids was varied but patterns emerged according to the lifestyle of the species, with the greatest structure shown by species that are highly habitat dependent and the least structure shown by oceanic species. Experimental designs of the underlying studies have, however, often been opportunistic with small sample sizes, few locations sampled and based on analysis of single mitochondrial regions and/or few microsatellite markers. The literature provides a basis for understanding the population genetic structure of IWP carcharhinids, but future research needs to focus on the application of population genomics and more robust experimental design so that population genetic structure can be quantified with higher certainty and resolution over finer spatial scales.

scholarly journals Spatial scales of genetic structure and gene flow inCalochortus albus(Liliaceae)

2013 ◽  
Vol 3 (6) ◽  
pp. 1461-1470 ◽  
Author(s):  
Jillian M. Henss ◽  
Jackson R. Moeller ◽  
Terra J. Theim ◽  
Thomas J. Givnish
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Spatial Scales

Host traits explain the genetic structure of parasites: a meta-analysis

Parasitology ◽  
2013 ◽  
Vol 140 (10) ◽  
pp. 1316-1322 ◽  
Author(s):  
ISABEL BLASCO-COSTA ◽  
ROBERT POULIN
Keyword(s):  
Life Cycle ◽  
Gene Flow ◽  
Genetic Structure ◽  
Spatial Scales ◽  
Meta Analysis ◽  
Dispersal Ability ◽  
Trematode Species ◽  
Genetic Structuring ◽  
Geographic Scale ◽  
Strong Correlate

SUMMARYGene flow maintains the genetic integrity of species over large spatial scales, and dispersal maintains gene flow among separate populations. However, body size is a strong correlate of dispersal ability, with small-bodied organisms being poor dispersers. For parasites, small size may be compensated by using their hosts for indirect dispersal. In trematodes, some species use only aquatic hosts to complete their life cycle, whereas others use birds or mammals as final hosts, allowing dispersal among separate aquatic habitats. We performed the first test of the universality of the type of life cycle as a driver of parasite dispersal, using a meta-analysis of 16 studies of population genetic structure in 16 trematode species. After accounting for the geographic scale of a study, the number of populations sampled, and the genetic marker used, we found the type of life cycle to be the best predictor of genetic structure (Fst): trematode species bound to complete their life cycle within water showed significantly more pronounced genetic structuring than those leaving water through a bird or mammal host. This finding highlights the dependence of parasites on host traits for their dispersal, suggesting that genetic differentiation of parasites reflects the mobility of their hosts.

Genetic structure and diversity of the black-throated finch (Poephila cincta) across its current range

2016 ◽  
Vol 64 (6) ◽  
pp. 375
Author(s):  
Lei Stanley Tang ◽  
Carolyn Smith-Keune ◽  
Anthony C. Grice ◽  
James M. Moloney ◽  
Britta Denise Hardesty
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Standard Error ◽  
Conservation Management ◽  
Spatial Scales ◽  
Mitochondrial Control Region ◽  
Population Connectivity ◽  
Population Declines ◽  
Genetic Structure And Diversity

Understanding the patterns of population connectivity and level of genetic diversity can facilitate the identification of both ecologically relevant populations and the spatial scales at which conservation management may need to focus. We quantified genetic variation within and among populations of black-throated finches across their current distribution. To quantify genetic structure and diversity, we genotyped 242 individuals from four populations using 14 polymorphic microsatellite markers and sequenced 25 individuals based on a 302-base-pair segment of mitochondrial control region. We found modest levels of genetic diversity (average allelic richness r = 4.37 ± 0.41 (standard error) and average heterozygosity HO = 0.42 ± 0.040 (standard error)) with no bottleneck signature among sampled populations. We identified two genetic groups that represent populations of two subspecies based on Bayesian clustering analysis and low levels of genetic differentiation based on pairwise genetic differentiation statistics (all FST, RST and Nei’s unbiased D values <0.1). Our data suggest that genetic exchange occurs among sampled populations despite recent population declines. Conservation efforts that focus on maintaining habitat connectivity and increasing habitat quality to ensure a high level of gene flow on a larger scale will improve the species’ ability to persist in changing landscapes. Conservation management should also support continuous monitoring of the bird to identify any rapid population declines as land-use intensification occurs throughout the species’ range.

Statistical phylogeographic tests of competing 'Lake Carpentaria hypotheses' in the mouth-brooding freshwater fish, Glossamia aprion (Apogonidae)

2012 ◽  
Vol 63 (5) ◽  
pp. 450 ◽  
Author(s):  
Benjamin D. Cook ◽  
Mark Adams ◽  
Peter B. Mather ◽  
Jane M. Hughes
Keyword(s):  
Gene Flow ◽  
Freshwater Fish ◽  
Late Pleistocene ◽  
Marine Species ◽  
Relative Strength ◽  
Population Connectivity ◽  
Freshwater Species ◽  
Recent Period ◽  
Past Population ◽  
Diadromous Species

Glacial cycles during the Pleistocene reduced sea levels and created new land connections in northern Australia, where many currently isolated rivers also became connected via an extensive paleo-lake system, ‘Lake Carpentaria’. However, the most recent period during which populations of freshwater species were connected by gene flow across Lake Carpentaria is debated: various ‘Lake Carpentaria hypotheses’ have been proposed. Here, we used a statistical phylogeographic approach to assess the timing of past population connectivity across the Carpentaria region in the obligate freshwater fish, Glossamia aprion. Results for this species indicate that the most recent period of genetic exchange across the Carpentaria region coincided with the mid- to late Pleistocene, a result shown previously for other freshwater and diadromous species. Based on these findings and published studies for various freshwater, diadromous and marine species, we propose a set of ‘Lake Carpentaria’ hypotheses to explain past population connectivity in aquatic species: (1) strictly freshwater species had widespread gene flow in the mid- to late Pleistocene before the last glacial maximum; (2) marine species were subdivided into eastern and western populations by land during Pleistocene glacial phases; and (3) past connectivity in diadromous species reflects the relative strength of their marine affinity.

Population genetic structures at multiple spatial scales: importance of social groups in European badgers

2020 ◽  
Vol 101 (5) ◽  
pp. 1380-1391
Author(s):  
Mickaël Jacquier ◽  
Jean-Michel Vandel ◽  
François Léger ◽  
Jeanne Duhayer ◽  
Sylvia Pardonnet ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Large Scale ◽  
Evolutionary Ecology ◽  
Spatial Scales ◽  
Geographic Distance ◽  
Threshold Value ◽  
Meles Meles ◽  
Genetic Structure Of Populations ◽  
Genetic Structures

Abstract Population viability and metapopulation dynamics are strongly affected by gene flow. Identifying ecological correlates of genetic structure and gene flow in wild populations is therefore a major issue both in evolutionary ecology and species management. Studying the genetic structure of populations also enables identification of the spatial scale at which most gene flow occurs, hence the scale of the functional connectivity, which is of paramount importance for species ecology. In this study, we examined the genetic structure of a social, continuously distributed mammal, the European badger (Meles meles), both at large spatial scales (among populations) and fine (within populations) spatial scales. The study was carried out in 11 sites across France utilizing a noninvasive hair trapping protocol at 206 monitored setts. We identified 264 badgers genotyped at 24 microsatellite DNA loci. At the large scale, we observed high and significant genetic differentiation among populations (global Fst = 0.139; range of pairwise Fst [0.046–0.231]) that was not related to the geographic distance among sites, suggesting few large-scale dispersal events. Within populations, we detected a threshold value below which badgers were genetically close (&lt; 400 m), highlighting that sociality is the major structuring process within badger populations at the fine scale.

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