Population structure and phylogenetic relationships of Ceutorhynchus neglectus (Coleoptera: Curculionidae)

2005 ◽  
Vol 137 (6) ◽  
pp. 672-684 ◽  
Author(s):  
R. D. Laffin ◽  
L. M. Dosdall ◽  
F.A.H. Sperling
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
North America ◽  
Phylogenetic Relationships ◽  
Nuclear Dna ◽  
Isolation By Distance ◽  
Coi Gene ◽  
Restricted Gene Flow ◽  
Species Variation ◽  
Internal Transcribed Spacer Region

AbstractCeutorhynchus neglectus Blatchley is a weevil that is native to, and widely distributed in, North America. It has life-history characteristics similar to its alien invasive congener, Ceutorhynchus obstrictus (Marsham), the cabbage seedpod weevil. Our study was undertaken to compare the population structure of C. neglectus in North America to that of C. obstrictus, which, in contrast, was introduced only recently to North America and might be expected to have a simpler population structure. We also compared the population structure of C. neglectus to that of Pissodes strobi (Peck), which is known to possess high levels of intraspecific variation and is also a Nearctic weevil. We sequenced a 790-bp fragment of mtDNA (cytochrome oxidase I (COI) gene) and a 117-bp fragment of nuclear DNA (internal transcribed spacer region 1 (ITS1)). Nested clade analysis inferred contiguous range expansion and restricted gene flow with isolation by distance. Analysis of molecular variance also supported restricted gene flow between geographically distant populations. However, within-species variation in C. neglectus was lower than that for other weevil species including C. obstrictus. We also examined DNA divergences and phylogenetic relationships among 10 species of Ceutorhynchus using parsimony analysis of a 2.3-kb fragment of mtDNA (COI–COII) and a 541-bp fragment of nuclear DNA (elongation factor 1α).

Genetic diversity of the lichen-forming alga, Diplosphaera chodatii, in North America and Europe

2013 ◽  
Vol 45 (6) ◽  
pp. 799-813 ◽  
Author(s):  
Kyle M. FONTAINE ◽  
Elfie STOCKER-WÖRGÖTTER ◽  
Tom BOOTH ◽  
Michele D. PIERCEY-NORMORE
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Gene Flow ◽  
North America ◽  
Isolation By Distance ◽  
Water Level Fluctuations ◽  
Free Living ◽  
Climatic Zones ◽  
Algal Symbiont ◽  
Low Levels

AbstractDermatocarpon luridum is a subaquatic lichen which is distributed within temperate climatic zones around the world. It colonizes rock substrata along the shoreline of lakes and rivers of watersheds that regularly experience water level fluctuations. The mycobiont produces perithecia with small, simple spores that are thought to be wind dispersed. The photobiont, Diplosphaera chodatii, occurs both free-living and lichenized but little is known about its distribution and dispersal. The goal of this study was to compare the population structure of the photobiont from lakes and rivers in central North America with those of Europe. Specimens were collected in Manitoba, Canada and Austria. Population structure of the algal symbiont was assessed using the internal transcribed spacer (ITS) of ribosomal DNA (rDNA) and actin gene sequences. Results showed that genetic diversity and gene flow was high within local populations, but gene flow was low between continental populations. Low levels of gene flow between the most distant populations support the isolation-by-distance theory. The photobiont on both continents is also reported to be the photobiont for other lichen species contributing to photobiont availability for D. luridum.

scholarly journals Population genetics of Aedes albopictus (Diptera: Culicidae) in its native range in Lao People’s Democratic Republic

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Maysa Tiemi Motoki ◽  
Dina Madera Fonseca ◽  
Elliott Frederic Miot ◽  
Bruna Demari-Silva ◽  
Phoutmany Thammavong ◽  
...  
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Aedes Albopictus ◽  
Isolation By Distance ◽  
Genetic Locus ◽  
Lao Pdr ◽  
Phylogenetic Network ◽  
Population Expansion ◽  
Recent Population Expansion ◽  
The Usa

Abstract Background The Asian tiger mosquito, Aedes (Stegomyia) albopictus (Skuse) is an important worldwide invasive species and can be a locally important vector of chikungunya, dengue and, potentially, Zika. This species is native to Southeast Asia where populations thrive in both temperate and tropical climates. A better understanding of the population structure of Ae. albopictus in Lao PDR is very important in order to support the implementation of strategies for diseases prevention and vector control. In the present study, we investigated the genetic variability of Ae. albopictus across a north-south transect in Lao PDR. Methods We used variability in a 1337-bp fragment of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1), to assess the population structure of Ae. albopictus in Lao PDR. For context, we also examined variability at the same genetic locus in samples of Ae. albopictus from Thailand, China, Taiwan, Japan, Singapore, Italy and the USA. Results We observed very high levels of genetic polymorphism with 46 novel haplotypes in Ae. albopictus from 9 localities in Lao PDR and Thailand populations. Significant differences were observed between the Luangnamtha population and other locations in Lao PDR. However, we found no evidence of isolation by distance. There was overall little genetic structure indicating ongoing and frequent gene flow among populations or a recent population expansion. Indeed, the neutrality test supported population expansion in Laotian Ae. albopictus and mismatch distribution analyses showed a lack of low frequency alleles, a pattern often seen in bottlenecked populations. When samples from Lao PDR were analyzed together with samples from Thailand, China, Taiwan, Japan, Singapore, Italy and the USA, phylogenetic network and Bayesian cluster analysis showed that most populations from tropical/subtropical regions are more genetically related to each other, than populations from temperate regions. Similarly, most populations from temperate regions are more genetically related to each other, than those from tropical/subtropical regions. Conclusions Aedes albopictus in Lao PDR are genetically related to populations from tropical/subtropical regions (i.e. Thailand, Singapore, and California and Texas in the USA). The extensive gene flow among locations in Lao PDR indicates that local control is undermined by repeated introductions from untreated sites.

A PCR primer set for determination of phylogenetic relationships of Bursaphelenchus species within the xylophilus group

Nematology ◽  
2002 ◽  
Vol 4 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Natsumi Kanzaki ◽  
Kazuyoshi Futai
Keyword(s):  
North America ◽  
Phylogenetic Relationships ◽  
Coniferous Forest ◽  
The Other ◽  
Coi Gene ◽  
Eurasian Continent ◽  
Dna Base ◽  
Base Sequences ◽  
Free Living Nematode

AbstractThe phylogenetic relationships of Bursaphelenchus conicaudatus with B. abruptus, B. fraudulentus, B. mucronatus and B. xylophilus species were analysed based on the DNA base sequences of 18S, 5.8S, ITS1 and ITS2 of rDNA and the partial code of mitochondrial cytochrome oxidase subunit I (COI) gene. The monophyly of B. abruptus and the other species in the xylophilus group was not supported, and B. abruptus could be excluded from the xylophilus group. The other species, i.e ., B. conicaudatus, B. fraudulentus, B. mucronatus and B. xylophilus were assumed to be monophyletic. The ancestor of these four species is assumed to have originated in the eastern part of the Eurasian continent as a free-living nematode inhabiting broad-leaved trees. First, B. conicaudatus branched from the ancestor in eastern Asia. Then B. fraudulentus and B. mucronatus separated from the ancestor. B. mucronatus changed its host from broad-leaved trees to conifers and spread throughout the coniferous forest over the Eurasian continent and North America. B. xylophilus might originate from a population of B. mucronatus remaining in North America after B. mucronatus had diversified.

scholarly journals Genetic diversity and extent of gene flow in the endangered Japanese population of Hodgson's hawk-eagle, Spizaetus nipalensis

2006 ◽  
Vol 16 (2) ◽  
pp. 113-129 ◽  
Author(s):  
SHIGEKI ASAI ◽  
YOSHIHIRO YAMAMOTO ◽  
SATOSHI YAMAGISHI
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Japanese Population ◽  
Isolation By Distance ◽  
Cladistic Analysis ◽  
Variable Region ◽  
Complete Sequence ◽  
Restricted Gene Flow ◽  
Critical Situation ◽  
Mtdna Sequence

The Japanese subspecies of Hodgson's Hawk-eagle, Spizaetus nipalensis orientalis, is considered threatened and has been designated as Endangered by the Japanese government. We determined the complete mitochondrial DNA (mtDNA) sequence of this species and designed a primer set to amplify a highly variable region of mtDNA, part of the control region (CR), based on this complete sequence. Using the primers, we amplified the CR and then determined the haplotypes of 178 samples collected at different sites in Japan. A nested cladistic analysis indicated that gene flow within some clades was restricted. The inference key implied that isolation by distance had caused the restriction of gene flow. Moreover, the ranges of the clades in which restricted gene flow was detected overlapped with the ranges of other clades. These results suggest that there is no fragmental population of Hodgson's Hawk-eagle in Japan and that this species has dispersed within short distances, at least in some lineages. Genetic diversity was high in comparison with other species. Therefore, at least in terms of genetic diversity, the Japanese population of Hodgson's Hawk-eagle is probably not in a critical situation.

scholarly journals Population structure and dispersal across small and large spatial scales in a direct developing marine isopod

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

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

scholarly journals Visualizing spatial population structure with estimated effective migration surfaces

2014 ◽  
Author(s):  
Desislava Petkova ◽  
John Novembre ◽  
Matthew Stephens
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Genetic Similarity ◽  
Large Scale ◽  
Genetic Model ◽  
Isolation By Distance ◽  
Genetic Data ◽  
Migration Rates ◽  
Spatial Population ◽  
Spatial Population Structure

Genetic data often exhibit patterns that are broadly consistent with "isolation by distance" - a phenomenon where genetic similarity tends to decay with geographic distance. In a heterogeneous habitat, decay may occur more quickly in some regions than others: for example, barriers to gene flow can accelerate the genetic differentiation between groups located close in space. We use the concept of "effective migration" to model the relationship between genetics and geography: in this paradigm, effective migration is low in regions where genetic similarity decays quickly. We present a method to quantify and visualize variation in effective migration across the habitat, which can be used to identify potential barriers to gene flow, from geographically indexed large-scale genetic data. Our approach uses a population genetic model to relate underlying migration rates to expected pairwise genetic dissimilarities, and estimates migration rates by matching these expectations to the observed dissimilarities. We illustrate the potential and limitations of our method using simulations and data from elephant, human, and Arabidopsis thaliana populations. The resulting visualizations highlight important features of the spatial population structure that are difficult to discern using existing methods for summarizing genetic variation such as principal components analysis.

scholarly journals Maintenance of Sympatric and Allopatric Populations in Free-Living Terrestrial Bacteria

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Alexander B. Chase ◽  
Philip Arevalo ◽  
Eoin L. Brodie ◽  
Martin F. Polz ◽  
Ulas Karaoz ◽  
...  
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Isolation By Distance ◽  
Dispersal Limitation ◽  
Genomic Diversity ◽  
Gene Content ◽  
Microbial Populations ◽  
Free Living ◽  
Phylogenetic Structure ◽  
Isolation By Environment

ABSTRACT For free-living bacteria and archaea, the equivalent of the biological species concept does not exist, creating several obstacles to the study of the processes contributing to microbial diversification. These obstacles are particularly high in soil, where high bacterial diversity inhibits the study of closely related genotypes and therefore the factors structuring microbial populations. Here, we isolated strains within a single Curtobacterium ecotype from surface soil (leaf litter) across a regional climate gradient and investigated the phylogenetic structure, recombination, and flexible gene content of this genomic diversity to infer patterns of gene flow. Our results indicate that microbial populations are delineated by gene flow discontinuities, with distinct populations cooccurring at multiple sites. Bacterial population structure was further delineated by genomic features allowing for the identification of candidate genes possibly contributing to local adaptation. These results suggest that the genetic structure within this bacterium is maintained both by ecological specialization in localized microenvironments (isolation by environment) and by dispersal limitation between geographic locations (isolation by distance). IMPORTANCE Due to the promiscuous exchange of genetic material and asexual reproduction, delineating microbial species (and, by extension, populations) remains challenging. Because of this, the vast majority of microbial studies assessing population structure often compare divergent strains from disparate environments under varied selective pressures. Here, we investigated the population structure within a single bacterial ecotype, a unit equivalent to a eukaryotic species, defined as highly clustered genotypic and phenotypic strains with the same ecological niche. Using a combination of genomic and computational analyses, we assessed the phylogenetic structure, extent of recombination, and flexible gene content of this genomic diversity to infer patterns of gene flow. To our knowledge, this study is the first to do so for a dominant soil bacterium. Our results indicate that bacterial soil populations, similarly to those in other environments, are structured by gene flow discontinuities and exhibit distributional patterns consistent with both isolation by distance and isolation by environment. Thus, both dispersal limitation and local environments contribute to the divergence among closely related soil bacteria as observed in macroorganisms.

Genetic variability in Indian populations of banana corm weevil [Cosmopolites sordidus (Coleoptera: Curculionidae)] assessed by RAPDs and AFLPs

2017 ◽  
Vol 37 (03) ◽  
pp. 149-162 ◽  
Author(s):  
Sweta Kumari U. Yadav ◽  
Jyotsna Singh ◽  
B. Padmanaban ◽  
Lalitha Sunil Kumar
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Hot Spot ◽  
Random Amplified Polymorphic Dna ◽  
Geographic Distance ◽  
Mantel Test ◽  
Cosmopolites Sordidus ◽  
Restricted Gene Flow ◽  
Control And Management ◽  
Economic Pest

AbstractCosmopolites sordidus(Germar), commonly known as banana corm weevil, is an important economic pest in Asia that can cause severe yield loss depending upon the stage at which infestation occurs. In spite of its economic importance, little is known about the population structure of this pest in India. Random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) were used to characterize the population genetic structure ofC. sordiduscollected from five hot spot locations in India. Nineteen RAPD primers and five selective AFLP primer combinations generated 147 and 304 amplification products, respectively. UPGMA dendrograms generated with both marker systems failed to reveal populations clustered based on geographic distance, which was confirmed by the Mantel test, which did not show a strong correlation between genetic distance and geographic distance. Values of indices of genetic identity showed that the populations were closely related. Though the gene flow estimate (Nm) between the populations was 0.469, suggesting restricted gene flow, the populations are not genetically distinct. These observations suggest that the range expansion of this banana pest in India has taken place through transport of infested corms and plant material, resulting in genetically close populations that are geographically distinct. These results provide important information on the population structure of this pest in India, which will aid in designing suitable strategies for its control and management, especially with respect to insecticide resistance.

scholarly journals Progressive colonization and restricted gene flow shape island-dependent population structure in Galápagos marine iguanas (Amblyrhynchus cristatus)

2009 ◽  
Vol 9 (1) ◽  
pp. 297 ◽  
Author(s):  
Sebastian Steinfartz ◽  
Scott Glaberman ◽  
Deborah Lanterbecq ◽  
Michael A Russello ◽  
Sabrina Rosa ◽  
...  
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Restricted Gene Flow ◽  
Amblyrhynchus Cristatus ◽  
Marine Iguanas

Life-history characteristics and landscape attributes as drivers of genetic variation, gene flow, and fine-scale population structure in northern Dolly Varden (Salvelinus malma malma) in Canada

2015 ◽  
Vol 72 (10) ◽  
pp. 1477-1493 ◽  
Author(s):  
Les N. Harris ◽  
Robert Bajno ◽  
Colin P. Gallagher ◽  
Itsuro Koizumi ◽  
Lucy K. Johnson ◽  
...  
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Life History ◽  
Gene Flow ◽  
Isolation By Distance ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Dolly Varden Salvelinus Malma ◽  
Northern Dolly Varden ◽  
Population Demographic

The northern Dolly Varden (Salvelinus malma malma) displays variable life-history types and occupies freshwater habitats with varying levels of connectivity. Here, we assayed microsatellite DNA variation in northern Dolly Varden from the western Canadian Arctic to resolve landscape and life-history variables driving variation in genetic diversity and population structure. Overall, genetic variation was highest in anadromous populations and lowest in those isolated above waterfalls, with stream-resident forms intermediate between the two. Anadromous and isolated populations were genetically divergent from each other, while no genetic differentiation was detectable between sympatric anadromous and stream-resident forms. Population structure was stable over 25 years, hierarchically organized, and conformed to an isolation-by-distance pattern, but stream-isolated forms often deviated from these patterns. Gene flow occurred primarily among Yukon North Slope populations and between sympatric anadromous and resident forms. These results were sex-dependent to some extent, but were influenced more by reproductive status and life history. Our study provides novel insights into the life history, population demographic, and habitat variables that shape the distribution of genetic variation and population structure in Arctic fluvial habitats while providing a spatial context for management and conservation.

Sign in / Sign up

Export Citation Format

Share Document