scholarly journals Genotyping‐by‐sequencing approach indicates geographic distance as the main factor affecting genetic structure and gene flow in Brazilian populations of Grapholita molesta (Lepidoptera, Tortricidae)

2015 ◽  
Vol 8 (5) ◽  
pp. 476-485 ◽  
Author(s):  
Karina Lucas Silva‐Brandão ◽  
Oscar Arnaldo Batista Neto e Silva ◽  
Marcelo Mendes Brandão ◽  
Celso Omoto ◽  
Felix A. H. Sperling
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Geographic Distance ◽  
Genotyping By Sequencing ◽  
Grapholita Molesta ◽  
Brazilian Populations ◽  
Main Factor

scholarly journals Population Genetic Structure of Rhizoctonia oryzae-sativae from Rice in Latin America and Its Adaptive Potential to Emerge as a Pathogen on Urochloa Pastures

2017 ◽  
Vol 107 (1) ◽  
pp. 121-131 ◽  
Author(s):  
Danilo A. dos Santos Pereira ◽  
Paulo C. Ceresini ◽  
Vanina L. Castroagudín ◽  
Lina M. Ramos-Molina ◽  
Edisson Chavarro-Mesa ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Reproductive System ◽  
Population Genetic ◽  
Upland Rice ◽  
Adaptive Potential ◽  
Rhizoctonia Oryzae ◽  
Hardy Weinberg Equilibrium ◽  
Two Populations ◽  
Brazilian Populations

The fungus Rhizoctonia oryzae-sativae is an important pathogen that causes the aggregated sheath spot disease on rice. In this study, we investigated the genetic structure of rice-adapted populations of R. oryzae-sativae sampled from traditional rice-cropping areas from the Paraíba Valley, São Paulo, Brazil, and from Meta, in the Colombian Llanos, in South America. We used five microsatellite loci to measure population differentiation and infer the pathogen’s reproductive system. Gene flow was detected among the three populations of R. oryzae-sativae from lowland rice in Brazil and Colombia. In contrast, a lack of gene flow was observed between the lowland and the upland rice populations of the pathogen. Evidence of sexual reproduction including low clonality, Hardy-Weinberg equilibrium within loci and gametic equilibrium between loci, indicated the predominance of a mixed reproductive system in all populations. In addition, we assessed the adaptive potential of the Brazilian populations of R. oryzae-sativae to emerge as a pathogen to Urochloa spp. (signalgrass) based on greenhouse aggressiveness assays. The Brazilian populations of R. oryzae-sativae were probably only incipiently adapted as a pathogen to Urochloa spp. Comparison between RST and QST showed the predominance of diversifying selection in the divergence between the two populations of R. oryzae-sativae from Brazil.

Genetic Structure and Gene Flow Among Brazilian Populations of Heliothis virescens (Lepidoptera: Noctuidae)

2012 ◽  
Vol 105 (6) ◽  
pp. 2136-2146 ◽  
Author(s):  
Felipe A. Domingues ◽  
Karina L. Silva-Brandão ◽  
Aluana G. Abreu ◽  
Omaththage P. Perera ◽  
Carlos A. Blanco ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Heliothis Virescens ◽  
Lepidoptera Noctuidae ◽  
Brazilian Populations

scholarly journals A strategic sampling design revealed the local genetic structure of cold-water fluvial sculpin: a focus on groundwater-dependent water temperature heterogeneity

2021 ◽  
Author(s):  
Souta Nakajima ◽  
Masanao Sueyoshi ◽  
Shun K. Hirota ◽  
Nobuo Ishiyama ◽  
Ayumi Matsuo ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Low Temperature ◽  
Genetic Differentiation ◽  
Water Temperature ◽  
Sampling Design ◽  
Cold Water ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
Sampling Strategy ◽  
Genotyping By Sequencing

A key piece of information for ecosystem management is the relationship between the environment and population genetic structure. However, it is difficult to clearly quantify the effects of environmental factors on genetic differentiation because of spatial autocorrelation and analytical problems. In this study, we focused on stream ecosystems and the environmental heterogeneity caused by groundwater and constructed a sampling design in which geographic distance and environmental differences are not correlated. Using multiplexed ISSR genotyping by sequencing (MIG-seq) method, a fine-scale population genetics study was conducted in fluvial sculpin Cottus nozawae, for which summer water temperature is the determinant factor in distribution and survival. There was a clear genetic structure in the watershed. Although a significant isolation-by-distance pattern was detected in the watershed, there was no association between genetic differentiation and water temperature. Instead, asymmetric gene flow from relatively low-temperature streams to high-temperature streams was detected, indicating the importance of low-temperature streams and continuous habitats. The groundwater-focused sampling strategy yielded unexpected results and provided important insights for conservation.

scholarly journals Landscape genomics of an obligate mutualism: discordant population structures between a leafcutter-ant and its fungal cultivars

2018 ◽  
Author(s):  
Chad C. Smith ◽  
Jesse N. Weber ◽  
Alexander S. Mikheyev ◽  
Flavio Roces ◽  
Martin Bollazzi ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Abiotic Factors ◽  
Genotyping By Sequencing ◽  
Range Limit ◽  
Range Margin ◽  
Landscape Genomics ◽  
Temperature And Precipitation ◽  
Obligate Mutualism

AbstractTo explore landscape genomics at the range limit of an obligate mutualism, we used genotyping-by-sequencing (ddRADseq) to quantify population structure and the effect of hostsymbiont interactions between the northernmost fungus-farming leafcutter ant Atta texana and its two main types of cultivated fungus. At local scales, genome-wide differentiation between ants associated with either of the two fungal types is greater than the differentiation associated with the abiotic factors temperature and precipitation, suggesting that specific ant-fungus genome-genome combinations may have been favored by selection. For the ant hosts, we found a broad cline of genetic structure across the range, and a reduction of genetic diversity along the axis of range expansion towards the range margin. In contrast, genetic structure was patchy in the cultivated fungi, with no consistent reduction of fungal genetic diversity at the range margins. This discordance in population-genetic structure between ant hosts and fungal symbionts is surprising because the ant farmers co-disperse with their vertically-transmitted fungal symbionts, but apparently the fungi disperse occasionally also through between-nest horizontal transfer or other unknown dispersal mechanisms. The discordance in populationgenetic structure indicates that genetic drift and gene flow differ in magnitude between each partner in this leafcutter mutualism. Together, these findings imply that variation in the strength of drift and gene flow experienced by each mutualistic partner affects adaptation to environmental stress at the range margin, and genome-genome interactions between host and symbiont influences adaptive genetic differentiation of the host during range evolution in this obligate mutualism.

Genetic diversity and gene flow patterns in two riverine plant species with contrasting life-history traits and distributions across a large inland floodplain

2020 ◽  
Vol 68 (5) ◽  
pp. 384
Author(s):  
William Higgisson ◽  
Dianne Gleeson ◽  
Linda Broadhurst ◽  
Fiona Dyer
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Water Resource ◽  
Isolation By Distance ◽  
Spatial Genetic Structure ◽  
Geographic Distance ◽  
Resource Development ◽  
Water Resource Development ◽  
Floodplain River

Gene flow is a key evolutionary driver of spatial genetic structure, reflecting demographic processes and dispersal mechanisms. Understanding how genetic structure is maintained across a landscape can assist in setting conservation objectives. In Australia, floodplains naturally experience highly variable flooding regimes that structure the vegetation communities. Flooding plays an important role, connecting communities on floodplains and enabling dispersal via hydrochory. Water resource development has changed the lateral-connectivity of floodplain-river systems. One possible consequence of these changes is reduced physical and subsequent genetic connections. This study aimed to identify and compare the population structure and dispersal patterns of tangled lignum (Duma florulenta) and river cooba (Acacia stenophylla) across a large inland floodplain using a landscape genetics approach. Both species are widespread throughout flood prone areas of arid and semiarid Australia. Tangled lignum occurs on floodplains while river cooba occurs along rivers. Leaves were collected from 144 tangled lignum plants across 10 sites and 84 river cooba plants across 6 sites, on the floodplain of the lower and mid Lachlan River, and the Murrumbidgee River, NSW. DNA was extracted and genotyped using DArTseq platforms (double digest RADseq). Genetic diversity was compared with floodplain-river connection frequency, and genetic distance (FST) was compared with river distance, geographic distance and floodplain-river connection frequency between sites. Genetic similarity increased with increasing floodplain-river connection frequency in tangled lignum but not in river cooba. In tangled lignum, sites that experience more frequent flooding had greater genetic diversity and were more genetically homogenous. There was also an isolation by distance effect where increasing geographic distance correlated with increasing genetic differentiation in tangled lignum, but not in river cooba. The distribution of river cooba along rivers facilitates regular dispersal of seeds via hydrochory regardless of river level, while the dispersal of seeds of tangled lignum between patches is dependent on flooding events. The genetic impact of water resource development may be greater for species which occur on floodplains compared with species along river channels.

scholarly journals Bird migratory flyways influence the phylogeography of the invasive brine shrimp Artemia franciscana in its native American range

2013 ◽  
Author(s):  
Joaquín Muñoz ◽  
Francisco Amat ◽  
Andy J Green ◽  
Jordi Figuerola ◽  
Africa Gómez
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Brine Shrimp ◽  
Population Genetic ◽  
Geographic Distance ◽  
Artemia Franciscana ◽  
Large Set ◽  
Native Range ◽  
Mantel Tests

Since Darwin’s time, waterbirds have been considered an important vector for the dispersal of continental aquatic invertebrates. Bird movements have facilitated the worldwide invasion of the American brine shrimp Artemia franciscana, transporting cysts (diapausing eggs), and favouring rapid range expansions from introduction sites. Here we address the impact of bird migratory flyways on the population genetic structure and phylogeography of A. franciscana in its native range in the Americas. We examined the sequence variation for two mitochondrial gene fragments (COI and 16S for a subset of the data) in a large set of population samples representing the entire native range of A. franciscana. Furthermore, we performed Mantel tests and redundancy analyses (RDA) to test the role of flyways, geography and human introductions on the phylogeography and population genetic structure at a continental scale. A. franciscanamitochondrial DNA was very diverse, with two main clades, largely corresponding to Pacific and Atlantic populations, mirroring American bird flyways. There was a high degree of regional endemism, with populations subdivided into at least 12 divergent, geographically restricted and largely allopatric mitochondrial lineages, and high levels of population structure ( Φ ST of 0.92), indicating low ongoing gene flow. We found evidence of human-mediated introductions in nine out of 39 populations analysed. Once these populations were removed, Mantel tests revealed a strong association between genetic variation and geographic distance (i.e., isolation-by-distance pattern). RDA showed that shared bird flyways explained around 20% of the variance in genetic distance between populations and this was highly significant, once geographic distance was controlled for. The variance explained increased to 30% when the factor human introduction was included in the model. Our findings suggest that bird-mediated transport of brine shrimp propagules does not result in substantial ongoing gene flow; instead, it had a significant historical role on the current species phylogeography, facilitating the colonisation of new aquatic environments as they become available along their main migratory flyways.

Population genetic structure and secondary endosymbionts of Q Bemisia tabaci (Hemiptera: Aleyrodidae) from Greece

2012 ◽  
Vol 102 (3) ◽  
pp. 353-365 ◽  
Author(s):  
A. Tsagkarakou ◽  
L. Mouton ◽  
J.B. Kristoffersen ◽  
E. Dokianakis ◽  
M. Grispou ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Bemisia Tabaci ◽  
Molecular Diversity ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
Cultivated Plants ◽  
High Frequencies ◽  
Genetic Groups ◽  
Aegean Islands

AbstractWe investigated the molecular diversity of the major agricultural pest Bemisia tabaci and of its associated secondary endosymbionts in Greece. Analyzing mitochondrial DNA, we found that the Q1 (=Q west) is predominant. We used eight microsatellite polymorphic markers to study the genetic structure of 37 populations from mainland and insular Greece, collected on different host species from outdoor and protected crops as well as from non-cultivated plants. In some cases, gene flow was found to be low even between populations separated by just a few kilometres. Bayesian analysis identified two main genetic groups, the first encompassing populations from south Crete and the second composed of populations from north Crete, two other Aegean islands and mainland Greece. Genetic differentiation was not correlated with different host plant species or habitat, or greenhouse versus open environment populations. Gene flow significantly decreased with geographic distance, but no isolation by distance existed when only the samples from mainland Greece or only the samples from Crete were considered. The secondary symbionts Wolbachia and Hamiltonella were present at high frequencies while Arsenophonus, Cardinium and Rickettsia were absent from Greek populations. Multilocus sequence typing of Wolbachia identified two Wolbachia strains. These two strains were found together in most of the populations studied but never in the same host individual. Their role on the observed population structure is discussed.

scholarly journals Population genetic structure of the lettuce root aphid, Pemphigus bursarius (L.), in relation to geographic distance, gene flow and host plant usage

Heredity ◽  
2003 ◽  
Vol 91 (3) ◽  
pp. 217-223 ◽  
Author(s):  
N J Miller ◽  
A J Birley ◽  
A D J Overall ◽  
G M Tatchell
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Host Plant ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Geographic Distance ◽  
Pemphigus Bursarius

Effects of oceanographic circulation on the gene flow, genetic structure, and phylogeography of the rosethorn rockfish (Sebastes helvomaculatus)

1999 ◽  
Vol 56 (5) ◽  
pp. 803-813 ◽  
Author(s):  
Axayácatl Rocha-Olivares ◽  
Russell D Vetter
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Ocean Circulation ◽  
Dna Sequences ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Geographic Distance ◽  
Haplotype Diversity ◽  
Gulf Of Alaska ◽  
High Dispersal

The genetic structure and phylogeography of 88 rosethorn rockfish (Sebastes helvomaculatus) from five localities (California, Oregon, British Columbia, and two in the Gulf of Alaska) were analyzed using DNA sequences from the mitochondrial control region. High levels of genetic diversity (h > 85%) and significant population genetic structure (FST = 0.13, P < 0.001; AMOVA ΦST = 0.15, P << 0.001) were found. A significant genetic break was detected (ΦCT = 0.22, P << 0.001) coinciding with the transition zone between the Oregonian and Aleutian zoogeographic provinces and consistent with retention and dispersal mechanisms associated with the oceanographic circulation of the region. A correlation between geographic distance and population genetic distance supported the hypothesis of gene flow dominated by pelagic-phase dispersal. Oregonian province populations had higher haplotype diversity, with >70% of the individuals representing a recent lineage absent in the Aleutian province. This suggests a limited northward dispersal across the zoogeographic boundary. The phylogeographic stucture may be due to a founder effect in the Aleutian province or an ocean circulation driven pseudo-vicariance. These results demonstrate that organisms with protracted pelagic-phase stages and high dispersal capability can exhibit population genetic structure that reflects their historical demography and present dispersal patterns.

scholarly journals Genetic Structure of Mexican Spotted Owl (Strix Occidentalis Lucida) Populations in a Fragmented Landscape

The Auk ◽  
2006 ◽  
Vol 123 (4) ◽  
pp. 1090-1102 ◽  
Author(s):  
George F. Barrowclough ◽  
Jeff G. Groth ◽  
Lisa A. Mertz ◽  
R. J. Gutiérrez
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
Variance Partitioning ◽  
Fragmented Landscape ◽  
Spotted Owl ◽  
Strix Occidentalis ◽  
Strix Occidentalis Lucida ◽  
Central Arizona

Abstract We used mitochondrial DNA control-region sequences to investigate the genetic structure of Mexican Spotted Owl (Strix occidentalis lucida) populations in the southwestern United States. This subspecies is federally listed as threatened, and its preferred habitat is naturally fragmented. We found that intrapopulation genetic diversity was high in all but the southeastern Arizona “sky island” populations, where it was variable. Genetic variance partitioning indicated that ≈17% of the variation was distributed among populations and 7.5% was distributed among physiographic regions. Patterns of genetic correlation with geographic distance indicated that gene flow was substantial among populations within the relatively continuous habitat zone of the Mogollon Rim-Upper Gila Mountains in central Arizona and west-central New Mexico. However, there was significant isolation-by-distance elsewhere, and estimates of genetic divergence increased exponentially with geographic distance among fragmented populations on the scale of a few hundreds of kilometers; this implies that gene flow is restricted among those habitat fragments. Genetic heterogeneity among southeastern Arizona populations suggest that they have regularly received immigrants from the central Arizona populations. The Colorado population either was larger than thought or, more likely, has continuously received immigrants from elsewhere and is not a self-sustaining population. Estructura Genética de las Poblaciones de Strix occidentalis lucida en un Paisaje Fragmentado

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