Contemporary and historical oceanographic processes explain genetic connectivity in a Southwestern Atlantic coral
TL;DR: This study examined population genetic structure and migration patterns of the coral Mussismilia hispida, one of the main reef builders in the Southwestern Atlantic Ocean, using hyper-variable markers and a fine sampling scale to enlighten the population dynamics.
Abstract: Understanding connectivity patterns has implications for evolutionary and ecological processes, as well as for proper conservation strategies. This study examined population genetic structure and migration patterns of the coral Mussismilia hispida, one of the main reef builders in the Southwestern Atlantic Ocean. For this, 15 sites were sampled along its entire distributional range employing 10 microsatellite loci. M. hispida was divided into five genetically differentiated populations by Structure analysis. Population structure and migration estimates are consistent with present-day oceanographic current patterns, zones of upwelling and historical sea-level changes. The Central Region and Oceanic Islands populations had the highest genetic diversity, were possibly the main sources of migrants for other populations and presented mutual migrant exchange. This mutual exchange and the high diversity of Oceanic Islands, a peripherical population, is highly interesting and unexpected, but can be explained if these sites acted as refugia in past low sea-level stance. This is the first connectivity study in the region using hyper-variable markers and a fine sampling scale along 3,500 km. These results enlighten the population dynamics of an important reef building species and shows how oceanographic processes may act as barriers to dispersal for marine species, providing valuable information for management strategies.
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Dissertation•
01 Jan 2002
554 citations
33 citations
Cites background from "Contemporary and historical oceanog..."
...For example, Peluso et al. (2018) detected migration and connectivity of the reef- building coral M. hispida between the Eastern Brazil and oceanic islands....
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...The MEs may provide a more continuous area of suitable habitat for this coral, favouring the maintenance of gene flow between the Trindade Island, Rocas Atoll and Fernando de Noronha Archipelago through the oceanic currents (Peluso et al., 2018)....
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TL;DR: The validation of three FATM and a trophic index for coral reef ecology studies are validated and the in situ occurrences of shifts between feeding modes are described, while highlighting the role of temperature and meteorological events.
Abstract: Many species of reef-building corals are mixotrophic, relying on both photoautotrophy performed by their dinoflagellate symbionts and heterotrophy from consumption of zooplankton. Autotrophy and heterotrophy supply corals with specific ω3 fatty acids, which can be used as trophic markers and record the contribution of each feeding strategy. This study investigated whether the reef-building coral Mussismilia hispida, endemic to Brazil, is able to shift between predominantly autotrophic and predominantly heterotrophic by monitoring the concentration of fatty acids in the host tissue. We then examined whether shifts are related to changes in temperature and wind stress. For that purpose, M. hispida colonies were monitored for a year with monthly tissue sampling. Symbiont concentration was determined and lipid extraction performed. Four fatty acids were quantitatively analyzed by gas chromatography with flame ionization detector: the autotrophy markers: stearidonic acid (SDA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and a heterotrophy marker: cis-gondoic acid (CGA). Three preliminary experiments confirmed the specificity of SDA, DPA and CGA, but not of DHA. Shifts of predominance occurred multiple times during the year and were associated with minimal temperatures and wind stress. Colonies underwent mild bleaching during summer months, which they seemed to compensate with heterotrophic feeding. Our major findings include the validation of three FATM and a trophic index for coral reef ecology studies and also describing the in situ occurrences of shifts between feeding modes, while highlighting the role of temperature and meteorological events.
31 citations
Cites background from "Contemporary and historical oceanog..."
...the Brazilian coast (Castro and Pires 2001; Oigman-Pszczol and Creed 2004; Leão et al. 2016; Peluso et al. 2018), is able to shift between predominantly autotrophic and pre-...
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...…coral, Mussismilia hispida, a massive species endemic to and widely distributed along the Brazilian coast (Castro and Pires 2001; Oigman-Pszczol and Creed 2004; Leão et al. 2016; Peluso et al. 2018), is able to shift between predominantly autotrophic and predominantly heterotrophic feeding....
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TL;DR: Results suggest that the divergent clades in G. caudata correspond to distinct ecotypes in the process of incipient speciation and thus should be considered for the management policy of this commercially important species.
Abstract: In this study, we explored how past terrestrial and marine climate changes have interacted to shape the phylogeographic patterns of the intertidal red seaweed Gracilaria caudata, an economically important species exploited for agar production in the Brazilian north‐east. Seven sites were sampled along the north‐east tropical and south‐east sub‐tropical Brazilian coast. The genetic diversity and structure of G. caudata was inferred using a combination of mitochondrial (COI and cox2‐3), chloroplast (rbcL) and 15 nuclear microsatellite markers. A remarkable congruence between nuclear, mitochondrial and chloroplast data revealed clear separation between the north‐east (from 03° S to 08° S) and the south‐east (from 20° S to 23° S) coast of Brazil. These two clades differ in their demographic histories, with signatures of recent demographic expansions in the north‐east and divergent populations in the south‐east, suggesting the maintenance of several refugia during the last glacial maximum due to sea‐level rise and fall. The Bahia region (around 12o S) occupies an intermediate position between both clades. Microsatellites and mtDNA markers showed additional levels of genetic structure within each sampled site located south of Bahia. The separation between the two main groups in G. caudata is likely recent, probably occurring during the Quaternary glacial cycles. The genetic breaks are concordant with (1) those separating terrestrial refugia, (2) major river outflows and (3) frontiers between tropical and subtropical regions. Taken together with previously published eco‐physiological studies that showed differences in the physiological performance of the strains from distinct locations, these results suggest that the divergent clades in G. caudata correspond to distinct ecotypes in the process of incipient speciation and thus should be considered for the management policy of this commercially important species.
17 citations
Cites background from "Contemporary and historical oceanog..."
...…da Silva Cortinhas et al. 2016; in the king fish Menticirrhus americanus, dos Santos Freitas et al. 2017; in the white shrimp Litopenaeus schmitt Maggioni et al. 2003; in the coral Mussismilia hispida Peluso et al. 2018) and in the red mangrove tree Rhizophora mangle (Francisco et al. 2018)....
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...1; Santos et al. 2006, da Silva Cortinhas et al. 2016, dos Santos Freitas et al. 2017, Peluso et al. 2018) than to demographic processes linked to Pleistocene climatic changes....
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...Similar to our study, several phylogeographic studies have described one or two major genetic breaks along the Brazilian coast in invertebrate and vertebrate marine species (in the king weakfish, Macrodon ancylodon, Santos et al. 2006; in the silver fish Atherinella brasiliensis, da Silva Cortinhas et al. 2016; in the king fish Menticirrhus americanus, dos Santos Freitas et al. 2017; in the white shrimp Litopenaeus schmitt Maggioni et al. 2003; in the coral Mussismilia hispida Peluso et al. 2018) and in the red mangrove tree Rhizophora mangle (Francisco et al. 2018)....
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...…S–23° S, separating the tropical populations located along the coast where the Brazil Current flows from the sub-tropical populations influenced by cooler South Atlantic Central Waters (SACW; Santos et al. 2006, da Silva Cortinhas et al. 2016, dos Santos Freitas et al. 2017, Peluso et al. 2018)....
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...…barrier is located at 4° S–6° S, separating the populations of northern Brazil from those of central Brazil (Santos et al. 2006, Francisco et al. 2018, Peluso et al. 2018) and the second one occurs at 21° S–23° S, separating the tropical populations located along the coast where the Brazil Current…...
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TL;DR: This study examined the diversity of Symbiodiniaceae associated with the scleractinian coral Favia gravida across its distributional range using the ITS-2 marker and showed that F. gravida exhibits some degree of flexibility in its symbiotic association with zooxanthellae across its range.
Abstract: Zooxanthellate corals live in symbiosis with phototrophic dinoflagellates of the family Symbiodiniaceae, enabling the host coral to dwell in shallow, nutrient-poor marine waters. The South Atlantic Ocean is characterized by low coral diversity with high levels of endemism. However, little is known about coral-dinoflagellate associations in the region. This study examined the diversity of Symbiodiniaceae associated with the scleractinian coral Favia gravida across its distributional range using the ITS-2 marker. This brooding coral endemic to the South Atlantic can be found across a wide range of latitudes and longitudes, including the Mid-Atlantic islands. Even though it occurs primarily in shallower environments, F. gravida is among the few coral species that live in habitats with extreme environmental conditions (high irradiance, temperature, and turbidity) such as very shallow tide pools. In the present study, we show that F. gravida exhibits some degree of flexibility in its symbiotic association with zooxanthellae across its range. F. gravida associates predominantly with Cladocopium C3 (ITS2 type Symbiodinium C3) but also with Symbiodinium A3, Symbiodinium linucheae (ITS2 type A4), Cladocopium C1, Cladocopium C130, and Fugacium F3. Symbiont diversity varied across biogeographic regions (Symbiodinium A3 and S. linucheae were found in the Tropical Eastern Atlantic, Cladocopium C1 in the Mid-Atlantic, and other subtypes in the Southwestern Atlantic) and was affected by local environmental conditions. In addition, Symbiodiniaceae diversity was highest in a southwestern Atlantic oceanic island (Rocas Atoll). Understanding the relationship between corals and their algal symbionts is critical in determining the factors that control the ecological niches of zooxanthellate corals and their symbionts, and identifying host-symbiont pairs that may be more resistant to environmental changes.
15 citations
References
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TL;DR: Pritch et al. as discussed by the authors proposed a model-based clustering method for using multilocus genotype data to infer population structure and assign individuals to populations, which can be applied to most of the commonly used genetic markers, provided that they are not closely linked.
Abstract: We describe a model-based clustering method for using multilocus genotype data to infer population structure and assign individuals to populations. We assume a model in which there are K populations (where K may be unknown), each of which is characterized by a set of allele frequencies at each locus. Individuals in the sample are assigned (probabilistically) to populations, or jointly to two or more populations if their genotypes indicate that they are admixed. Our model does not assume a particular mutation process, and it can be applied to most of the commonly used genetic markers, provided that they are not closely linked. Applications of our method include demonstrating the presence of population structure, assigning individuals to populations, studying hybrid zones, and identifying migrants and admixed individuals. We show that the method can produce highly accurate assignments using modest numbers of loci— e.g. , seven microsatellite loci in an example using genotype data from an endangered bird species. The software used for this article is available from http://www.stats.ox.ac.uk/~pritch/home.html.
27,454 citations
TL;DR: STRUCTURE HARVESTER is presented, a web-based program for collating results generated by the program STRUCTURE, which provides a fast way to assess and visualize likelihood values across multiple values of K and hundreds of iterations for easier detection of the number of genetic groups that best fit the data.
Abstract: We present STRUCTURE HARVESTER (available at http://taylor0.biology.ucla.edu/structureHarvester/
), a web-based program for collating results generated by the program STRUCTURE. The program provides a fast way to assess and visualize likelihood values across multiple values of K and hundreds of iterations for easier detection of the number of genetic groups that best fit the data. In addition, STRUCTURE HARVESTER will reformat data for use in downstream programs, such as CLUMPP.
9,960 citations
TL;DR: MICRO - CHECKER estimates the frequency of null alleles and, importantly, can adjust the allele and genotype frequencies of the amplified alleles, permitting their use in further population genetic analysis.
Abstract: DNA degradation, low DNA concentrations and primer-site mutations may result in the incorrect assignment of microsatellite genotypes, potentially biasing population genetic analyses. MICRO - CHECKER is WINDOWS ®-based software that tests the genotyping of microsatellites from diploid populations. The program aids identification of genotyping errors due to nonamplified alleles (null alleles), short allele dominance (large allele dropout) and the scoring of stutter peaks, and also detects typographic errors. MICRO - CHECKER estimates the frequency of null alleles and, importantly, can adjust the allele and genotype frequencies of the amplified alleles, permitting their use in further population genetic analysis. MICRO CHECKER can be freely downloaded from http://www.microchecker.hull.ac.uk/.
9,953 citations
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TL;DR: GenAlEx: Genetic Analysis in Excel is a cross-platform package for population genetic analyses that runs within Microsoft Excel that offers analysis of diploid codominant, haploid and binary genetic loci and DNA sequences.
Abstract: Summary: GenAlEx: Genetic Analysis in Excel is a cross-platform package for population genetic analyses that runs within Microsoft Excel. GenAlEx offers analysis of diploid codominant, haploid and binary genetic loci and DNA sequences. Both frequency-based (F-statistics, heterozygosity, HWE, population assignment, relatedness) and distance-based (AMOVA, PCoA, Mantel tests, multivariate spatial autocorrelation) analyses are provided. New features include calculation of new estimators of population structure: G′ST, G′′ST, Jost’s Dest and F′ST through AMOVA, Shannon Information analysis, linkage disequilibrium analysis for biallelic data and novel heterogeneity tests for spatial autocorrelation analysis. Export to more than 30 other data formats is provided. Teaching tutorials and expanded step-by-step output options are included. The comprehensive guide has been fully revised.
Availability and implementation: GenAlEx is written in VBA and provided as a Microsoft Excel Add-in (compatible with Excel 2003, 2007, 2010 on PC; Excel 2004, 2011 on Macintosh). GenAlEx, and supporting documentation and tutorials are freely available at: http://biology.anu.edu.au/GenAlEx.
Contact: rod.peakall@anu.edu.au
9,564 citations
7,669 citations