scholarly journals Genetic Differentiation and Phylogeography of Rotifer Polyarthra Dolichoptera and P. Vulgaris Complexes Between Southern China and Eastern North America: High Intercontinental Differences

2021 ◽  
Author(s):  
Diwen Liang ◽  
George McManus ◽  
Qing Wang ◽  
Xian Sun ◽  
Zhiwei Liu ◽  
...  
Keyword(s):  
Gene Flow ◽  
North America ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Cryptic Species ◽  
Environmental Changes ◽  
Southern China ◽  
Geographic Distance ◽  
Eastern North America ◽  
Long Distance

Abstract Genetic differentiations and phylogeographical patterns of small organisms may be shaped by spatial isolation, environmental gradients and gene flow. However, knowledge about genetic differentiation of rotifers on intercontinental gradient is still limited. Polyarthra dolichoptera and P. vulgaris are cosmopolitan rotifers and tolerant to environmental changes, offering an excellent model to address the research gap. Here, we investigated the populations in Southern China and eastern North America, and evaluated the phylogeographical patterns from their geographical range sizes, geographic-genetic distance relationships and their response to spatial-environmental factors. Using mitichondrial cytochrome c oxidase subunit I gene as the DNA marker, we analyzed a total of 170 individuals. At least 24 putative cryptic species, including 20 of P. dolichoptera and 4 of P. vulgaris were detected based on three delimitation methods. Our results showed that some cryptic species were widely distributed but most of them were limited to single areas. The divergence of P. dolichoptera and P. vulgaris complexes indicated that gene flow between continents was limited while that within each continent was stronger. Furthermore, on the intercontinental scale spatial distance had a stronger influence than physicochemical variables on the genetic differentiations of P. dolichoptera and P. vulgaris complexes. However, the relationship between genetic distance and geographic distance was not continuously linear and the P. dolichoptera data best fitted the power-law model. This might be due to the effects of habitat heterogeneity, long-distance colonization and oceanographic barriers. Outliers above the correlation line between geographic distance and genetic distance suggest a significant dispersal barrier on large geographic scales studies.

scholarly journals Genetic differentiation in an endangered and strongly philopatric, migrant shorebird

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nelli Rönkä ◽  
Veli-Matti Pakanen ◽  
Angela Pauliny ◽  
Robert L. Thomson ◽  
Kimmo Nuotio ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Differentiation ◽  
Environmental Changes ◽  
Isolation By Distance ◽  
Population Subdivision ◽  
Genetic Structuring ◽  
Long Distance ◽  
Mobile Species ◽  
High Dispersal ◽  
The Baltic

Abstract Background Populations living in fragmented habitats may suffer from loss of genetic variation and reduced between-patch dispersal, which are processes that can result in genetic differentiation. This occurs frequently in species with reduced mobility, whereas genetic differentiation is less common among mobile species such as migratory birds. The high dispersal capacity in the latter species usually allows for gene flow even in fragmented landscapes. However, strongly philopatric behaviour can reinforce relative isolation and the degree of genetic differentiation. The Southern Dunlin (Calidris alpina schinzii) is a philopatric, long-distance migratory shorebird and shows reduced dispersal between isolated breeding patches. The endangered population of the Southern Dunlin breeding at the Baltic Sea has suffered from habitat deterioration and fragmentation of coastal meadows. We sampled DNA across the entire population and used 12 polymorphic microsatellite loci to examine whether the environmental changes have resulted in genetic structuring and loss of variation. Results We found a pattern of isolation-by-distance across the whole Baltic population and genetic differentiation between local populations, even within the southern Baltic. Observed heterozygosity was lower than expected throughout the range and internal relatedness values were positive indicating inbreeding. Conclusions Our results provide long-term, empirical evidence for the theoretically expected links between habitat fragmentation, population subdivision, and gene flow. They also demonstrate a rare case of genetic differentiation between populations of a long-distance migratory species. The Baltic Southern Dunlin differs from many related shorebird species that show near panmixia, reflecting its philopatric life history and the reduced connectivity of its breeding patches. The results have important implications as they suggest that reduced connectivity of breeding habitats can threaten even long-distance migrants if they show strong philopatry during breeding. The Baltic Southern Dunlin warrants urgent conservation efforts that increase functional connectivity and gene flow between breeding areas.

scholarly journals Genetic differentiation between conspecific populations of Merodon avidus A (Diptera, Syrphidae)

2004 ◽  
pp. 33-44 ◽  
Author(s):  
Vesna Milankov ◽  
Jasmina Ludoski ◽  
Ante Vujic
Keyword(s):  
Gene Flow ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Selection Pressure ◽  
Geographic Distance ◽  
Inverse Function ◽  
Lower Degree ◽  
Allozyme Variability ◽  
Population Pair ◽  
Biogeographical Regions

Allozyme variability of populations of Merodon avidus A (M i l a n - k o v et al., 2001) from Dubasnica Mountain (Serbia), Morinj Bay (Montenegro) and Pindos Mountain (Greece) was analysed. The influence of gene flow on genetic differentiation among populations from the three biogeographical regions was also investigated. Genetic differentiaiton quantified by the Fst value, which is an inverse function of gene flow between populations, seemed to be correlated to both geographic and genetic distance (D, N e i, 1978), Namely in the population pairs Morinj - Dubasnica (253 km air distance), Morinj - Pindos (390km air distance) genetic differentiation and genetic distance increased with the geographic distance (Fst = 0.133, D = 0.022 and Fst = 0.309, D = 0.052, respectively). The exception was the population pair Dubasnica - Pindos (500 km air distance), where a lower degree of genetic differentiation was observed (Fst = 0.266; D = 0.047) than was expected based solely on the geographic distance. Results of this study suggest that that genetic differentiation among conspecific populations depends not only on the number of migrants (i. e. gene flow), but also on different selection pressure in different habits.

scholarly journals Geographic Distribution of Cryptic Species of Plasmopara viticola Causing Downy Mildew on Wild and Cultivated Grape in Eastern North America

2014 ◽  
Vol 104 (7) ◽  
pp. 692-701 ◽  
Author(s):  
Mélanie Rouxel ◽  
Pere Mestre ◽  
Anton Baudoin ◽  
Odile Carisse ◽  
Laurent Delière ◽  
...  
Keyword(s):  
North America ◽  
Cryptic Species ◽  
Downy Mildew ◽  
Geographic Distribution ◽  
Host Species ◽  
Large Scale ◽  
Plasmopara Viticola ◽  
Eastern North America ◽  
Grape Downy Mildew ◽  
Parthenocissus Quinquefolia

The putative center of origin of Plasmopara viticola, the causal agent of grape downy mildew, is eastern North America, where it has been described on several members of the family Vitaceae (e.g., Vitis spp., Parthenocissus spp., and Ampelopsis spp.). We have completed the first large-scale sampling of P. viticola isolates across a range of wild and cultivated host species distributed throughout the above region. Sequencing results of four partial genes indicated the presence of a new P. viticola species on Vitis vulpina in Virginia, adding to the four cryptic species of P. viticola recently recorded. The phylogenetic analysis also indicated that the P. viticola species found on Parthenocissus quinquefolia in North America is identical to Plasmopara muralis in Europe. The geographic distribution and host range of five pathogen species was determined through analysis of the internal transcribed spacer polymorphism of 896 isolates of P. viticola. Among three P. viticola species found on cultivated grape, one was restricted to Vitis interspecific hybrids within the northern part of eastern North America. A second species was recovered from V. vinifera and V. labrusca, and was distributed across most of the sampled region. A third species, although less abundant, was distributed across a larger geographical range, including the southern part of eastern North America. P. viticola clade aestivalis predominated (83% of isolates) in vineyards of the European winegrape V. vinifera within the sampled area, indicating that a single pathogen species may represent the primary threat to the European host species within eastern North America.

scholarly journals Large-scale geographic survey provides insights into the colonization history of a major aphid pest on its cultivated apple host in Europe, North America and North Africa

2020 ◽  
Author(s):  
S.G. Olvera-Vazquez ◽  
C. Remoue ◽  
A. Venon ◽  
A. Rousselet ◽  
O. Grandcolas ◽  
...  
Keyword(s):  
Gene Flow ◽  
North America ◽  
Genetic Differentiation ◽  
North Africa ◽  
Large Scale ◽  
Demographic History ◽  
High Genetic Diversity ◽  
The North ◽  
The Us ◽  
History Of

With frequent host shifts involving the colonization of new hosts across large geographical ranges, crop pests are good models for examining the mechanisms of rapid colonization. The microbial partners of pest insects may be involved or affected by colonization, which has been little studied so far. We investigated the demographic history of the rosy apple aphid, Dysaphis plantaginea, a major pest of the cultivated apple (Malus domestica) in Europe, North Africa and North America, as well as the diversity of its endosymbiotic bacterial community. We genotyped a comprehensive sample of 714 colonies from Europe, Morocco and the US using mitochondrial (CytB and CO1), bacterial (16s rRNA and TrnpB), and 30 microsatellite markers. We detected five populations spread across the US, Morocco, Western and Eastern Europe, and Spain. Populations showed weak genetic differentiation and high genetic diversity, except the Moroccan and the North American that are likely the result of recent colonization events. Coalescent-based inferences releaved high levels of gene flow among populations during the colonization, but did not allow determining the sequence of colonization of Europe, America and Morroco by D. plantaginea, likely because of the weak genetic differentiation and the occurrence of gene flow among populations. Finally, we found that D. plantaginea rarely hosts any other endosymbiotic bacteria than its obligate nutritional symbiont Buchnera aphidicola. This suggests that secondary endosymbionts did not play any role in the rapid spread of the rosy apple aphid. These findings have fundamental importance for understanding pest colonization processes and implications for sustainable pest control programs.

scholarly journals Evolutionary history of two cryptic species of Northern African jerboas

2019 ◽  
Author(s):  
Ana Filipa Moutinho ◽  
Nina Serén ◽  
Joana Paupério ◽  
Teresa Luísa Silva ◽  
Fernando Martínez-Freiría ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Cryptic Species ◽  
Evolutionary History ◽  
Demographic History ◽  
Habitat Specialization ◽  
Geographic Scale ◽  
Long Distance ◽  
Ecological Divergence ◽  
Geographic Population

Abstract Background Evidence suggests that complex paleoclimatic and geological events help shape species distributions, thus affecting their evolutionary history. In Sahara-Sahel, climatic oscillations shifted the desert extent during the Pliocene-Pleistocene interval, triggering the diversification of several species. Here, we investigated how these biogeographical and ecological events have shaped patterns of genetic diversity and divergence in African Jerboas, desert specialist species. We focused on two sister and cryptic species, Jaculus jaculus and J. hirtipes , where we (1) evaluated their genetic differentiation, (2) reconstructed their evolutionary and demographic history; (3) tested the level of gene flow between them, and (4) assessed their ecological niche divergence. Results The analyses based on 231 individuals sampled throughout North Africa, 8 sequence fragments (one mitochondrial and seven single copy nuclear DNA, including two candidate genes for fur coloration: MC1R and Agouti ), 6 microsatellite markers and ecological modelling revealed: (1) two distinct genetic lineages with overlapping distributions, in agreement with their classification as different taxa, J. jaculus and J. hirtipes , with (2) low levels of gene flow and strong species delimitation, (3) high genetic diversity but no apparent geographic population structure within species, suggesting long-distance migration between remote locations, and (4) low level of large-scale ecological divergence between the two taxa, suggesting species micro-habitat specialization. Conclusions Overall, our results suggest a speciation event that occurred during the Pliocene-Pleistocene transition. The contemporary distribution of genetic variation suggests ongoing population expansions, demonstrating the ability of these species for fast and long-range dispersal. Despite the largely overlapping distributions at a macrogeographic scale, our genetic results suggest that the two species remain reproductively isolated, as only negligible levels of gene flow were observed. The overlapping ecological preferences at a macro-geographic scale and the ecological divergence at the micro-habitat scale suggest that local adaptation may have played a crucial role in the speciation process of these species.

Canada lynx gene flow across a mountain transition zone in western North America

2020 ◽  
Author(s):  
Cristen M Watt ◽  
Elizabeth M Kierepka ◽  
Catarina C. Ferreira ◽  
Erin L Koen ◽  
Jeffrey R. Row ◽  
...  
Keyword(s):  
Gene Flow ◽  
North America ◽  
Rocky Mountains ◽  
Forest Cover ◽  
Geographic Distance ◽  
Lynx Lynx ◽  
Western North America ◽  
Ecological Divergence ◽  
Canada Lynx ◽  
Barrier Effects

Mountain ecotones have the potential to cause multiple patterns in divergence, from simple barrier effects to more fundamental ecological divergence. Most work in mountain ecotones in North America has focused on reinforcement between refugial populations, making prediction of how mountains impact species that are not restricted to separate glacial refugia remains difficult. This study focused on the Canada lynx (Lynx canadensis Kerr, 1792), a highly mobile felid considered to be a habitat and dietary specialist. Specifically, we used 14 microsatellite loci and landscape genetic tools to investigate if the Rocky Mountains and associated climatic transitions influence lynx genetic differentiation in western North America. Although lynx exhibited high gene flow across the region, analyses detected structuring of neutral genetic variation across our study area. Gene flow for lynx most strongly related to temperature and elevation compared to other landscape variables (terrain roughness, percent forest cover, and habitat suitability index) and geographic distance alone. Overall, genetic structure in lynx is most consistent with barrier effects created by the Rocky Mountains rather than ecological divergence. Furthermore, warmer temperatures had a measurable impact on gene flow, which suggests connectivity may further decrease in peripheral or fragmented populations as climate warms.

Comparing the genetic structure of codling moth Cydia pomonella (L.) from Greece and France: long distance gene-flow in a sedentary pest species

2011 ◽  
Vol 102 (2) ◽  
pp. 185-198 ◽  
Author(s):  
C.Ch. Voudouris ◽  
P. Franck ◽  
J. Olivares ◽  
B. Sauphanor ◽  
Z. Mamuris ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Insect Pest ◽  
Cydia Pomonella ◽  
Codling Moth ◽  
Pest Species ◽  
Long Distance ◽  
Control Programs ◽  
Genetic Clusters

AbstractCodling moth Cydia pomonella L. (Lepidoptera: Tortricidae) is the most important insect pest of apple production in Europe. Despite the economic importance of this pest, there is not information about the genetic structure of its population in Greece and the patterns of gene-flow which might affect the success of control programs. In this study, we analysed nine samples from apple, pear and walnut from various regions of mainland Greece using 11 microsatellite loci. Six samples from the aforementioned hosts from southern France were also examined for comparison. Bayesian clustering and genetic distance analyses separated the codling moth samples in two genetic clusters. The first cluster consisted mainly of the individuals from Greece, and the second of those from France, although admixture and miss-classified individuals were also observed. The low genetic differentiation among samples within each country was also revealed by FST statistics (0.009 among Greek samples and 0.0150 among French samples compared to 0.050 global value among all samples and 0.032 the mean of the pair-wise values between the two countries). These FST values suggest little structuring at large geographical scales in agreement with previous published studies. The host species and local factors (climatic conditions, topography, pest control programs) did not affect the genetic structure of codling moth populations within each country. The results are discussed in relation to human-made activities that promote gene-flow even at large geographic distances. Possible factors for the genetic differentiation between the two genetic clusters are also discussed.

Genetic structure and proposed conservation strategy for natural populations of Calycanthus chinensis Cheng et S.Y. Chang (Calycanthaceae)

2008 ◽  
Vol 88 (1) ◽  
pp. 179-186 ◽  
Author(s):  
Chu-Chuan Fan ◽  
Nicola Pecchioni ◽  
Long-Qing Chen
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Gene Diversity ◽  
Genetic Relationships ◽  
Natural Populations ◽  
Population Level ◽  
Conservation Strategy ◽  
Information Index

Calycanthus chinensis Cheng et S.Y. Chang, a tertiary relic species in China, is a shade-loving and deciduous bush withan elegant shape and beautiful flower of high ornamental value. It was widely planted in gardens and miniature scapes in China.The objective of this study was to characterize the genetic variation and structure in the three extant populations of the species, in order to provide useful information for a future conservation strategy. Twenty-two of 120 RAPD primers were selected and a total of 257 stable and clear DNA fragments were scored. Calycanthus chinensis showed a lower level of genetic diversity. At the population level, the percentage of polymorphic loci, Nei's gene diversity and Shannon’s information index were 40.9%, 0.1641 and 0.2386, respectively; while at the species level, the corresponding values were 59.1%, 0.2097 and 0.3123, respectively. The estimates of genetic differentiation based on Shannon’s information index (0.2360), Nei’s gene diversity (0.2175) and AMOVA (24.94%) were very similar, and significantly higher than the average genetic differentiation reported in outcrossed spermatophyte. So it suggested high genetic differentiation emerged among populations of C. chinensis. Genetic relationships among populations were assessed by Nei’s standard genetic distance, which suggested that the Tiantai population was genetically distinct from the other two populations. Moreover, the genetic distance was significantly correlated with geographical distance among populations (r = 0.997, t > t0.05). The gene flow (Nm) was 0.8994, indicating that gene exchange among populations was restricted. A conservation strategy was proposed based on the low gene flow and habitat deterioration, which are contributing to the endangered status of this species. Key words: Genetic diversity, endangered plant, population genetics, RAPD

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