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1.
Andrea M. Bernard Kevin A. Feldheim Michael R. Heithaus Sabine P. Wintner Bradley M. Wetherbee Mahmood S. Shivji 《Molecular ecology》2016,25(21):5312-5329
Knowledge of genetic connectivity dynamics in the world's large‐bodied, highly migratory, apex predator sharks across their global ranges is limited. One such species, the tiger shark (Galeocerdo cuvier), occurs worldwide in warm temperate and tropical waters, uses remarkably diverse habitats (nearshore to pelagic) and possesses a generalist diet that can structure marine ecosystems through top‐down processes. We investigated the phylogeography and the global population structure of this exploited, phylogenetically enigmatic shark by using 10 nuclear microsatellites (n = 380) and sequences from the mitochondrial control region (CR, n = 340) and cytochrome oxidase I gene (n = 100). All three marker classes showed the genetic differentiation between tiger sharks from the western Atlantic and Indo‐Pacific ocean basins (microsatellite FST > 0.129; CR ΦST > 0.497), the presence of North vs. southwestern Atlantic differentiation and the isolation of tiger sharks sampled from Hawaii from other surveyed locations. Furthermore, mitochondrial DNA revealed high levels of intraocean basin matrilineal population structure, suggesting female philopatry and sex‐biased gene flow. Coalescent‐ and genetic distance‐based estimates of divergence from CR sequences were largely congruent (dcorr = 0.0015–0.0050), indicating a separation of Indo‐Pacific and western Atlantic tiger sharks <1 million years ago. Mitochondrial haplotype relationships suggested that the western South Atlantic Ocean was likely a historical connection for interocean basin linkages via the dispersal around South Africa. Together, the results reveal unexpectedly high levels of population structure in a highly migratory, behaviourally generalist, cosmopolitan ocean predator, calling for management and conservation on smaller‐than‐anticipated spatial scales. 相似文献
2.
Le Qin Choo Thijs M. P. Bal Erica Goetze Katja T. C. A. Peijnenburg 《Journal of evolutionary biology》2021,34(1):224-240
Pteropods, a group of holoplanktonic gastropods, are regarded as bioindicators of the effects of ocean acidification on open ocean ecosystems, because their thin aragonitic shells are susceptible to dissolution. While there have been recent efforts to address their capacity for physiological acclimation, it is also important to gain predictive understanding of their ability to adapt to future ocean conditions. However, little is known about the levels of genetic variation and large‐scale population structuring of pteropods, key characteristics enabling local adaptation. We examined the spatial distribution of genetic diversity in the mitochondrial cytochrome c oxidase I (COI) and nuclear 28S gene fragments, as well as shell shape variation, across a latitudinal transect in the Atlantic Ocean (35°N–36°S) for the pteropod Limacina bulimoides. We observed high levels of genetic variability (COI π = 0.034, 28S π = 0.0021) and strong spatial structuring (COI ΦST = 0.230, 28S ΦST = 0.255) across this transect. Based on the congruence of mitochondrial and nuclear differentiation, as well as differences in shell shape, we identified a primary dispersal barrier in the southern Atlantic subtropical gyre (15–18°S). This barrier is maintained despite the presence of expatriates, a gyral current system, and in the absence of any distinct oceanographic gradients in this region, suggesting that reproductive isolation between these populations must be strong. A secondary dispersal barrier supported only by 28S pairwise ΦST comparisons was identified in the equatorial upwelling region (between 15°N and 4°S), which is concordant with barriers observed in other zooplankton species. Both oceanic dispersal barriers were congruent with regions of low abundance reported for a similar basin‐scale transect that was sampled 2 years later. Our finding supports the hypothesis that low abundance indicates areas of suboptimal habitat that result in barriers to gene flow in widely distributed zooplankton species. Such species may in fact consist of several populations or (sub)species that are adapted to local environmental conditions, limiting their potential for adaptive responses to ocean changes. Future analyses of genome‐wide diversity in pteropods could provide further insight into the strength, formation and maintenance of oceanic dispersal barriers. 相似文献
3.
Genetic diversity and structure in Fagus crenata were studied by analyzing 14 nuclear microsatellite loci in 23 populations distributed throughout the species’ range. Although
population differentiation was very low (F
ST = 0.027; R
ST = 0.041), both neighbor-joining tree and Bayesian clustering analyses provided clear evidence of genetic divergence between
populations along the Japan Sea (Japan Sea lineage) and Pacific (Pacific lineage) sides of Japan, indicating that physical
barriers to migration and gene flow, notably the mountain ranges separating the populations along the Japan Sea and Pacific
sides, have promoted genetic divergence between these populations. The two lineages of the nuclear genome are generally consistent
with those of the chloroplast genome detected in a previous study, with several discrepancies between the two genomes. Within-population
genetic diversity was generally very high (average H
E = 0.839), but decreased in a clinal fashion from southwest to northeast, largely among populations of the Japan Sea lineage.
This geographical gradient may have resulted from the late-glacial and postglacial recolonization to the northeast, which
led to a loss of within-population genetic diversity due to cumulative founder effects. 相似文献
4.
To offset declines in commercial landings of the softshell clam, Mya
arenaria, resource managers are engaged in extensive stocking of seed clams throughout its range in the northwest Atlantic. Because
a mixture of native and introduced stocks can disrupt locally adapted genotypes, we investigated genetic structure in M.
arenaria populations across its current distribution to test for patterns of regional differentiation. We sequenced mitochondrial
cytochrome oxidase I for a total of 212 individuals from 12 sites in the northwest Atlantic (NW Atlantic), as well as two
introduced sites, the northeast Pacific (NE Pacific), and the North Sea Europe (NS Europe). Populations exhibited extremely
low genetic variation, with one haplotype dominating (65–100%) at all sites sampled. Despite being introduced in the last
150–400 years, both NE Pacific and NS Europe populations had higher diversity measures than those in the NW Atlantic and both
contained private haplotypes at frequencies of 10–27% consistent with their geographic isolation. While significant genetic
structure (F
ST = 0.159, P < 0.001) was observed between NW Atlantic and NS Europe, there was no evidence for genetic structure across the pronounced
environmental clines of the NW Atlantic. Reduced genetic diversity in mtDNA combined with previous studies reporting reduced
genetic diversity in nuclear markers strongly suggests a recent population expansion in the NW Atlantic, a pattern that may
result from the retreat of ice sheets during Pleistocene glacial periods. Lack of genetic diversity and regional genetic differentiation
suggests that present management strategies for the commercially important softshell clam are unlikely to have a significant
impact on the regional distribution of genetic variation, although the possibility of disrupting locally adapted stocks cannot
be excluded. 相似文献
5.
Pedro F. Fruet Eduardo R. Secchi Fábio Daura-Jorge Els Vermeulen Paulo A. C. Flores Paulo César Simões-Lopes Rodrigo Cézar Genoves Paula Laporta Juliana C. Di Tullio Thales Renato O. Freitas Luciano Dalla Rosa Victor Hugo Valiati Luciano B. Beheregaray Luciana M. Möller 《Conservation Genetics》2014,15(4):879-895
Knowledge about the ecology of bottlenose dolphins in the Southwestern Atlantic Ocean is scarce. Increased by-catch rates over the last decade in coastal waters of southern Brazil have raised concerns about the decline in abundance of local dolphin communities. Lack of relevant data, including information on population structure and connectivity, have hampered an assessment of the conservation status of bottlenose dolphin communities in this region. Here we combined analyses of 16 microsatellite loci and mitochondrial DNA (mtDNA) control region sequences to investigate genetic diversity, structure and connectivity in 124 biopsy samples collected over six communities of photographically identified coastal bottlenose dolphins in southern Brazil, Uruguay and central Argentina. Levels of nuclear genetic diversity were remarkably low (mean values of allelic diversity and heterozygosity across all loci were 3.6 and 0.21, respectively), a result that possibly reflects the small size of local dolphin communities. On a broad geographical scale, strong and significant genetic differentiation was found between bottlenose dolphins from southern Brazil–Uruguay (SB–U) and Bahía San Antonio (BSA), Argentina (AMOVA mtDNA ΦST = 0.43; nuclear FST = 0.46), with negligible contemporary gene flow detected based on Bayesian estimates. On a finer scale, moderate but significant differentiation (AMOVA mtDNA ΦST = 0.29; nuclear FST = 0.13) and asymmetric gene flow was detected between five neighbouring communities in SB–U. Based on the results we propose that BSA and SB–U represent two distinct evolutionarily significant units, and that communities from SB–U comprise five distinct Management Units (MUs). Under this scenario, conservation efforts should prioritize the areas in southern Brazil where dolphins from three MUs overlap in their home ranges and where by-catch rates are reportedly higher. 相似文献
6.
Leonardo Campagna Peter J. Van Coeverden de Groot Brenda L. Saunders Stephen N. Atkinson Diana S. Weber Markus G. Dyck Peter T. Boag Stephen C. Lougheed 《Ecology and evolution》2013,3(9):3152-3165
As global warming accelerates the melting of Arctic sea ice, polar bears (Ursus maritimus) must adapt to a rapidly changing landscape. This process will necessarily alter the species distribution together with population dynamics and structure. Detailed knowledge of these changes is crucial to delineating conservation priorities. Here, we sampled 361 polar bears from across the center of the Canadian Arctic Archipelago spanning the Gulf of Boothia (GB) and M'Clintock Channel (MC). We use DNA microsatellites and mitochondrial control region sequences to quantify genetic differentiation, estimate gene flow, and infer population history. Two populations, roughly coincident with GB and MC, are significantly differentiated at both nuclear (FST = 0.01) and mitochondrial (ΦST = 0.47; FST = 0.29) loci, allowing Bayesian clustering analyses to assign individuals to either group. Our data imply that the causes of the mitochondrial and nuclear genetic patterns differ. Analysis of mtDNA reveals the matrilineal structure dates at least to the Holocene, and is common to individuals throughout the species’ range. These mtDNA differences probably reflect both genetic drift and historical colonization dynamics. In contrast, the differentiation inferred from microsatellites is only on the scale of hundreds of years, possibly reflecting contemporary impediments to gene flow. Taken together, our data suggest that gene flow is insufficient to homogenize the GB and MC populations and support the designation of GB and MC as separate polar bear conservation units. Our study also provide a striking example of how nuclear DNA and mtDNA capture different aspects of a species demographic history. 相似文献
7.
Cytonuclear discordance in the Florida Everglades invasive Burmese python (Python bivittatus) population reveals possible hybridization with the Indian python (P. molurus)
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Margaret E. Hunter Nathan A. Johnson Brian J. Smith Michelle C. Davis John S. S. Butterfield Ray W. Snow Kristen M. Hart 《Ecology and evolution》2018,8(17):9034-9047
The invasive Burmese python (Python bivittatus) has been reproducing in the Florida Everglades since the 1980s. These giant constrictor snakes have caused a precipitous decline in small mammal populations in southern Florida following escapes or releases from the commercial pet trade. To better understand the invasion pathway and genetic composition of the population, two mitochondrial (mtDNA) loci across 1,398 base pairs were sequenced on 426 snakes and 22 microsatellites were assessed on 389 snakes. Concatenated mtDNA sequences produced six haplotypes with an average nucleotide and haplotype diversity of π = 0.002 and h = 0.097, respectively. Samples collected in Florida from morphologically identified P. bivittatus snakes were similar to published cytochrome oxidase 1 and cytochrome b sequences from both P. bivittatus and Python molurus and were highly divergent (genetic distances of 5.4% and 4.3%, respectively). The average number of microsatellite alleles and expected heterozygosity were NA = 5.50 and HE = 0.60, respectively. Nuclear Bayesian assignment tests supported two genetically distinct groups and an admixed group, not geographically differentiated. The effective population size (NE = 315.1) was lower than expected for a population this large, but reflected the low genetic diversity overall. The patterns of genetic diversity between mtDNA and microsatellites were disparate, indicating nuclear introgression of separate mtDNA lineages corresponding to cytonuclear discordance. The introgression likely occurred prior to the invasion, but genetic information on the native range and commercial trade is needed for verification. Our finding that the Florida python population is comprised of distinct lineages suggests greater standing variation for adaptation and the potential for broader areas of suitable habitat in the invaded range. 相似文献
8.
Genetic divergence between two phenotypically distinct bottlenose dolphin ecotypes suggests separate evolutionary trajectories
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Pedro F. Fruet Eduardo R. Secchi Juliana C. Di Tullio Paulo César Simões‐Lopes Fábio Daura‐Jorge Ana P. B. Costa Els Vermeulen Paulo A. C. Flores Rodrigo Cezar Genoves Paula Laporta Luciano B. Beheregaray Luciana M. Möller 《Ecology and evolution》2017,7(21):9131-9143
Due to their worldwide distribution and occupancy of different types of environments, bottlenose dolphins display considerable morphological variation. Despite limited understanding about the taxonomic identity of such forms and connectivity among them at global scale, coastal (or inshore) and offshore (or oceanic) ecotypes have been widely recognized in several ocean regions. In the Southwest Atlantic Ocean (SWA), however, there are scarce records of bottlenose dolphins differing in external morphology according to habitat preferences that resemble the coastal‐offshore pattern observed elsewhere. The main aim of this study was to analyze the genetic variability, and test for population structure between coastal (n = 127) and offshore (n = 45) bottlenose dolphins sampled in the SWA to assess whether their external morphological distinction is consistent with genetic differentiation. We used a combination of mtDNA control region sequences and microsatellite genotypes to infer population structure and levels of genetic diversity. Our results from both molecular marker types were congruent and revealed strong levels of structuring (microsatellites FST = 0.385, p < .001; mtDNA FST = 0.183, p < .001; ΦST = 0.385, p < .001) and much lower genetic diversity in the coastal than the offshore ecotype, supporting patterns found in previous studies elsewhere. Despite the opportunity for gene flow in potential “contact zones”, we found minimal current and historical connectivity between ecotypes, suggesting they are following discrete evolutionary trajectories. Based on our molecular findings, which seem to be consistent with morphological differentiations recently described for bottlenose dolphins in our study area, we recommend recognizing the offshore bottlenose dolphin ecotype as an additional Evolutionarily Significant Unit (ESU) in the SWA. Implications of these results for the conservation of bottlenose dolphins in SWA are also discussed. 相似文献
9.
Do plant populations on distinct inselbergs talk to each other? A case study of genetic connectivity of a bromeliad species in an Ocbil landscape
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Karina Vanessa Hmeljevski Alison Gonçalves Nazareno Marcelo Leandro Bueno Maurício Sedrez dos Reis Rafaela Campostrini Forzza 《Ecology and evolution》2017,7(13):4704-4716
Here, we explore the historical and contemporaneous patterns of connectivity among Encholirium horridum populations located on granitic inselbergs in an Ocbil landscape within the Brazilian Atlantic Forest, using both nuclear and chloroplast microsatellite markers. Beyond to assess the E. horridum population genetic structure, we built species distribution models across four periods (current conditions, mid‐Holocene, Last Glacial Maximum [LGM], and Last Interglacial) and inferred putative dispersal corridors using a least‐cost path analysis to elucidate biogeographic patterns. Overall, high and significant genetic divergence was estimated among populations for both nuclear and plastid DNA (ΦST(n) = 0.463 and ΦST(plastid) = 0.961, respectively, p < .001). For nuclear genome, almost total absence of genetic admixture among populations and very low migration rates were evident, corroborating with the very low estimates of immigration and emigration rates observed among E. horridum populations. Based on the cpDNA results, putative dispersal routes in Sugar Loaf Land across cycles of climatic fluctuations in the Quaternary period revealed that the populations’ connectivity changed little during those events. Genetic analyses highlighted the low genetic connectivity and long‐term persistence of populations, and the founder effect and genetic drift seemed to have been very important processes that shaped the current diversity and genetic structure observed in both genomes. The genetic singularity of each population clearly shows the need for in situ conservation of all of them. 相似文献
10.
J. K. SCHULTZ K. A. FELDHEIM S. H. GRUBER M. V. ASHLEY T. M. MCGOVERN B. W. BOWEN 《Molecular ecology》2008,17(24):5336-5348
Seascapes are complex environments, and populations are often isolated by factors other than distance. Here we investigate the role of coastal habitat preference and philopatry in shaping the distribution and population structure of lemon sharks. The genus Negaprion comprises the amphiatlantic lemon shark (N. brevirostris), with a relict population in the eastern Pacific, and its Indo‐West Pacific sister species, the sicklefin lemon shark (N. acutidens). Analyzing 138 individuals throughout the range of N. brevirostris (N = 80) and N. acutidens (N = 58) at microsatellite loci (nine and six loci, respectively) and the mitochondrial control region, we find evidence of allopatric speciation corresponding to the Tethys Sea closure (10–14 million years ago) and isolation of the eastern Pacific N. brevirostris population via the emergence of the Isthmus of Panama (~3.5 million years ago). There is significant isolation by oceanic distance (R2 = 0.89, P = 0.005), defined as the maximum distance travelled at depths greater than 200 m. We find no evidence for contemporary transatlantic gene flow (m, M = 0.00) across an oceanic distance of ~2400 km. Negaprion acutidens populations in Australia and French Polynesia, separated by oceanic distances of at least 750 km, are moderately differentiated (FST = 0.070–0.087, P≤ 0.001; ΦST = 0.00, P = 0.99), with South Pacific archipelagos probably serving as stepping stones for rare dispersal events. Migration between coastally linked N. brevirostris populations is indicated by nuclear (m = 0.31) but not mitochondrial (m < 0.001) analyses, possibly indicating female natal site fidelity. However, philopatry is equivocal in N. acutidens, which has the lowest control region diversity (h = 0.28) of any shark yet studied. Restricted oceanic dispersal and high coastal connectivity stress the importance of both local and international conservation efforts for these threatened sharks. 相似文献
11.
Genetic connectivity among swarming sites in the wide ranging and recently declining little brown bat (Myotis lucifugus)
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Characterizing movement dynamics and spatial aspects of gene flow within a species permits inference on population structuring. As patterns of structuring are products of historical and current demographics and gene flow, assessment of structure through time can yield an understanding of evolutionary dynamics acting on populations that are necessary to inform management. Recent dramatic population declines in hibernating bats in eastern North America from white‐nose syndrome have prompted the need for information on movement dynamics for multiple bat species. We characterized population genetic structure of the little brown bat, Myotis lucifugus, at swarming sites in southeastern Canada using 9 nuclear microsatellites and a 292‐bp region of the mitochondrial genome. Analyses of FST, ΦST, and Bayesian clustering (STRUCTURE) found weak levels of genetic structure among swarming sites for the nuclear and mitochondrial genome (Global FST = 0.001, P < 0.05, Global ΦST = 0.045, P < 0.01, STRUCTURE K = 1) suggesting high contemporary gene flow. Hierarchical AMOVA also suggests little structuring at a regional (provincial) level. Metrics of nuclear genetic structure were not found to differ between males and females suggesting weak asymmetries in gene flow between the sexes. However, a greater degree of mitochondrial structuring does support male‐biased dispersal long term. Demographic analyses were consistent with past population growth and suggest a population expansion occurred from approximately 1250 to 12,500 BP, following Pleistocene deglaciation in the region. Our study suggests high gene flow and thus a high degree of connectivity among bats that visit swarming sites whereby mainland areas of the region may be best considered as one large gene pool for management and conservation. 相似文献
12.
Brenna A.
McLeod
Timothy R.
Frasier
Arthur S.
Dyke
James M.
Savelle
Bradley N.
White
《Marine Mammal Science》2012,28(4):E426-E443
Mitochondrial DNA (mtDNA) sequences were analyzed from 106 bowhead whale (Balaena mysticetus) specimens dating 471 ± 44 14C b.p. –10,290 ± 150 14C b.p. to evaluate whether historical changes in distribution and connectivity were detectable in levels of diversity and population structuring in the Central Canadian Arctic. The species has maintained levels of mtDNA diversity over 10,000 yr comparable to other nonbottlenecked large whale species. When compared to data from the Holocene East Greenland/Spitsbergen and contemporary Bering‐Chuckchi‐Beaufort populations, differentiation was low (FST≤ 0.005, ΦST≤ 0.003) and no temporal or geographical genetic structuring was evident. A combination of analyses suggests that the population has expanded over the past 30,000 14C yr. This genetic signature of expansion could result from population growth, admixture of multiple gene pools, or a combination of both scenarios. Despite known climatic change that altered bowhead distribution and led to isolation of populations, there is no detectable population structuring or change in genetic diversity during the Holocene. This may be due to long generation time, occasional population connectivity and a historically large global population. These characteristics warrant caution when interpreting contemporary bowhead whale DNA data, as it is unlikely that any population will be in mutation‐drift equilibrium. 相似文献
13.
Vítor Sousa Filipa Penha Maria J. Collares-Pereira Lounès Chikhi Maria M. Coelho 《Conservation Genetics》2008,9(4):791-805
The endemic and critically endangered cyprinid Chondrostoma lusitanicum has a very restricted distribution range. In order to estimate genetic diversity, characterize population structure and infer
the demographic history, we examined six microsatellite loci and cytochrome b (mtDNA) sequences from samples taken throughout C. lusitanicum’s geographical range. Estimates of genetic diversity were low in all samples (average He < 0.35). The microsatellite data
pointed to a major difference between northern (Samarra and Tejo drainages) and southern (Sado and Sines drainages) samples.
This separation was not so clear with mtDNA, since one sample from the Tejo drainage grouped with the southern samples. This
could be related with ancestral polymorphism or with admixture events between northern and southern sites during the late
Pleistocene. Nevertheless, both markers indicate high levels of population differentiation in the north (for microsatellites
F
ST > 0.23; and for mtDNA ΦST > 0.74) and lower levels in the south (F
ST < 0.05; ΦST < 0.40). With microsatellites we detected strong signals of a recent population decrease in effective size, by more than
one order of magnitude, starting in the last centuries. This is consistent with field observations reporting a severe anthropogenic-driven
population decline in the last decades. On the contrary mtDNA suggested a much older expansion. Overall, these results suggest
that the distribution of genetic diversity in C. lusitanicum is the result of both ancient events related with drainage system formation, and recent human activities. The potential effect
of population substructure generating genetic patterns similar to a population decrease is discussed, as well as the implications
of these results for the conservation of C. lusitanicum.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
Karen K. Martien Robin W. Baird Nicole M. Hedrick Antoinette M. Gorgone Janet L. Thieleking Daniel J. McSweeney Kelly M. Robertson Daniel L. Webster 《Marine Mammal Science》2012,28(3):E208-E232
We used mitochondrial and nuclear genetic markers to investigate population structure of common bottlenose dolphins, Tursiops truncatus, around the main Hawaiian Islands. Though broadly distributed throughout the world's oceans, bottlenose dolphins are known to form small populations in coastal waters. Recent photo‐identification data suggest the same is true in Hawaiian waters. We found genetic differentiation among (mtDNA ΦST= 0.014–0.141, microsatellite F’ST= 0.019–0.050) and low dispersal rates between (0.17–5.77 dispersers per generation) the main Hawaiian Island groups. Our results are consistent with movement rates estimated from photo‐identification data and suggest that each island group supports a demographically independent population. Inclusion in our analyses of samples collected near Palmyra Atoll provided evidence that the Hawaiian Islands are also occasionally visited by members of a genetically distinct, pelagic population. Two of our samples exhibited evidence of partial ancestry from Indo‐Pacific bottlenose dolphins (T. aduncus), a species not known to inhabit the Hawaiian Archipelago. Our findings have important implications for the management of Hawaiian bottlenose dolphins and raise concerns about the vulnerability to human impacts of pelagic species in island ecosystems. 相似文献
15.
C. C. D'Aloia S. M. Bogdanowicz R. G. Harrison P. M. Buston 《Molecular ecology》2014,23(12):2902-2913
Detecting patterns of spatial genetic structure (SGS) can help identify intrinsic and extrinsic barriers to gene flow within metapopulations. For marine organisms such as coral reef fishes, identifying these barriers is critical to predicting evolutionary dynamics and demarcating evolutionarily significant units for conservation. In this study, we adopted an alternative hypothesis‐testing framework to identify the patterns and predictors of SGS in the Caribbean reef fish Elacatinus lori. First, genetic structure was estimated using nuclear microsatellites and mitochondrial cytochrome b sequences. Next, clustering and network analyses were applied to visualize patterns of SGS. Finally, logistic regressions and linear mixed models were used to identify the predictors of SGS. Both sets of markers revealed low global structure: mitochondrial ΦST = 0.12, microsatellite FST = 0.0056. However, there was high variability among pairwise estimates, ranging from no differentiation between sites on contiguous reef (ΦST = 0) to strong differentiation between sites separated by ocean expanses ≥ 20 km (maximum ΦST = 0.65). Genetic clustering and statistical analyses provided additional support for the hypothesis that seascape discontinuity, represented by oceanic breaks between patches of reef habitat, is a key predictor of SGS in E. lori. Notably, the estimated patterns and predictors of SGS were consistent between both sets of markers. Combined with previous studies of dispersal in E. lori, these results suggest that the interaction between seascape continuity and the dispersal kernel plays an important role in determining genetic connectivity within metapopulations. 相似文献
16.
Diana Alvarez-Prada 《Studies on Neotropical Fauna and Environment》2013,48(2):80-95
The Wattled Curassow (Crax globulosa, Cracidae, Aves) is a large bird living in the Western Amazon basin and a critically endangered species in the Colombian and in the Peruvian Amazon. We carried out the first population genetics analysis of this species employing six nuclear microsatellite markers and sequences of the mtND2 gene. The main results are as follows. (1) The levels of gene diversity were high for the overall population as well as for each of the three islands for both microsatellites and mtDNA. (2) A small amount of genetic differentiation among populations was found with both types of markers (FST = 0.027 for microsatellites and NST = 0.17 for mitochondrial sequences). (3) Using microsatellites, the Geneclass 2.0 software detected a low correct assignment of individuals to their respective populations. The Structure software only detected one gene pool for the entire area studied. These results are relevant for conservation efforts of this critically endangered species. 相似文献
17.
R. Fernández M. Schubert A. M. Vargas‐Velázquez A. Brownlow G. A. Víkingsson U. Siebert L. F. Jensen N. Øien D. Wall E. Rogan B. Mikkelsen W. Dabin A. H. Alfarhan S. A. Alquraishi K. A. S. Al‐Rasheid G. Guillot L. Orlando 《Molecular ecology resources》2016,16(1):266-276
The field of population genetics is rapidly moving into population genomics as the quantity of data generated by high‐throughput sequencing platforms increases. In this study, we used restriction‐site‐associated DNA sequencing (RADSeq) to recover genomewide genotypes from 70 white‐beaked (Lagenorhynchus albirostris) and 43 Atlantic white‐sided dolphins (L. acutus) gathered throughout their north‐east Atlantic distribution range. Both species are at a high risk of being negatively affected by climate change. Here, we provide a resource of 38 240 RAD‐tags and 52 981 nuclear SNPs shared between both species. We have estimated overall higher levels of nucleotide diversity in white‐sided (π = 0.0492 ± 0.0006%) than in white‐beaked dolphins (π = 0.0300 ± 0.0004%). White‐sided dolphins sampled in the Faroe Islands, belonging to two pods (N = 7 and N = 11), showed similar levels of diversity (π = 0.0317 ± 0.0007% and 0.0267 ± 0.0006%, respectively) compared to unrelated individuals of the same species sampled elsewhere (e.g. π = 0.0285 ± 0.0007% for 11 Scottish individuals). No evidence of higher levels of kinship within pods can be derived from our analyses. When identifying the most likely number of genetic clusters among our sample set, we obtained an estimate of two to four clusters, corresponding to both species and possibly, two further clusters within each species. A higher diversity and lower population structuring was encountered in white‐sided dolphins from the north‐east Atlantic, in line with their preference for pelagic waters, as opposed to white‐beaked dolphins that have a more patchy distribution, mainly across continental shelves. 相似文献
18.
Dayana Elizabeth Salas-Leiva Víctor Manuel Mayor-Durn Nelson Toro-Perea 《Aquatic Botany》2009,91(3):187-193
This study analyzed the genetic diversity and patterns of genetic structure in Colombian populations of Avicennia germinans L. using microsatellite loci. A lower genetic diversity was found on both the Caribbean (Ho = 0.439) and the Pacific coasts (Ho = 0.277) than reported for the same species in other locations of Central American Pacific, suggesting the deterioration of genetic diversity. All the populations showed high inbreeding coefficients (0.131–0.462) indicating heterozygotes deficience. The genetic structure between the Colombian coasts separated by Central American Isthmus was high (FRT = 0.39) and the analyses of the genetic patterns of A. germinans revealed a clear differentiation of populations and no-recent gene flow evidence between coasts. Genetic structure was found within each coast (FST = 0.10 for the Caribbean coast and FST = 0.22 for the Pacific coast). The genetic patterns along the two coasts appear to reflect a forcing by local geomorphology and marine currents. Both coasts constitute a different Evolutionary Significant Unit, so we suggest for future transplantations plans that propagules or saplings of the populations of the Caribbean coast should not be mixed with those of the Pacific Colombian coast. Besides, we suggest that reforestation efforts should carefully distinguish propagules sources within each coast. 相似文献
19.
Phylogeography of Chinese cherry (Prunus pseudocerasus Lindl.) inferred from chloroplast and nuclear DNA: insights into evolutionary patterns and demographic history
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T. Chen Q. Chen Y. Luo Z.‐L. Huang J. Zhang H.‐R. Tang D.‐M. Pan X.‐R. Wang 《Plant biology (Stuttgart, Germany)》2015,17(4):787-797
Chinese cherry (Prunus pseudocerasus Lindl.) is a commercially valuable fruit crop in China. In order to obtain new insights into its evolutionary history and provide valuable recommendations for resource conservation, phylogeographic patterns of 26 natural populations (305 total individuals) from six geographic regions were analyzed using chloroplast and nuclear DNA fragments. Low levels of haplotype and nucleotide diversity were found in these populations, especially in landrace populations. It is likely that a combined effect of botanical characteristics impact the effective population size, such as inbreeding mating system, long life span, as well as vegetative reproduction. In addition, strong bottleneck effect caused by domestication, together with founder effect after dispersal and subsequent demographic expansion, might also accelerate the reduction of the genetic variation in landrace populations. Interestingly, populations from Longmen Mountain (LMM) and Daliangshan Mountain (DLSM) exhibited relatively higher levels of genetic diversity, inferring the two historical genetic diversity centers of the species. Moreover, moderate population subdivision was also detected by both chloroplast DNA (GST = 0.215; NST = 0.256) and nuclear DNA (GST = 0.146; NST = 0.342), respectively. We inferred that the episodes of efficient gene flow through seed dispersal, together with features of long generation cycle and inbreeding mating system, were likely the main contributors causing the observed phylogeographic patterns. Finally, factors that led to the present demographic patterns of populations from these regions and taxonomic varieties were also discussed. 相似文献
20.
Juan P. Torres‐Florez Rodrigo Hucke‐Gaete Howard Rosenbaum Christian C. Figueroa 《Ecology and evolution》2014,4(8):1398-1412
It is generally assumed that species with low population sizes have lower genetic diversities than larger populations and vice versa. However, this would not be the case for long‐lived species with long generation times, and which populations have declined due to anthropogenic effects, such as the blue whale (Balaenoptera musculus). This species was intensively decimated globally to near extinction during the 20th century. Along the Chilean coast, it is estimated that at least 4288 blue whales were hunted from an apparently pre‐exploitation population size (k) of a maximum of 6200 individuals (Southeastern Pacific). Thus, here, we describe the mtDNA (control region) and nDNA (microsatellites) diversities of the Chilean blue whale aggregation site in order to verify the expectation of low genetic diversity in small populations. We then compare our findings with other blue whale aggregations in the Southern Hemisphere. Interestingly, although the estimated population size is small compared with the pre‐whaling era, there is still considerable genetic diversity, even after the population crash, both in mitochondrial (N = 46) and nuclear (N = 52) markers (Hd = 0.890 and Ho = 0.692, respectively). Our results suggest that this diversity could be a consequence of the long generation times and the relatively short period of time elapsed since the end of whaling, which has been observed in other heavily‐exploited whale populations. The genetic variability of blue whales on their southern Chile feeding grounds was similar to that found in other Southern Hemisphere blue whale feeding grounds. Our phylogenetic analysis of mtDNA haplotypes does not show extensive differentiation of populations among Southern Hemisphere blue whale feeding grounds. The present study suggests that although levels of genetic diversity are frequently used as estimators of population health, these parameters depend on the biology of the species and should be taken into account in a monitoring framework study to obtain a more complete picture of the conservation status of a population. 相似文献