scholarly journals Admixture determines genetic diversity and population differentiation in the biological invasion of a lizard species

2008 ◽  
Vol 4 (4) ◽  
pp. 434-437 ◽  
Author(s):  
Jason J Kolbe ◽  
Allan Larson ◽  
Jonathan B Losos ◽  
Kevin de Queiroz
Keyword(s):  
Molecular Genetic ◽  
Genotypic Variation ◽  
Genotypic Diversity ◽  
Native Range ◽  
Adaptive Genetic Variation ◽  
Lizard Species ◽  
Microsatellite Variation ◽  
Introduced Populations ◽  
Haplotypic Diversity ◽  
Source Populations

Molecular genetic analyses show that introduced populations undergoing biological invasions often bring together individuals from genetically disparate native-range source populations, which can elevate genotypic variation if these individuals interbreed. Differential admixture among multiple native-range sources explains mitochondrial haplotypic diversity within and differentiation among invasive populations of the lizard Anolis sagrei . Our examination of microsatellite variation supports the hypothesis that lizards from disparate native-range sources, identified using mtDNA haplotypes, form genetically admixed introduced populations. Furthermore, within-population genotypic diversity increases with the number of sources and among-population genotypic differentiation reflects disparity in their native-range sources. If adaptive genetic variation is similarly restructured, then the ability of invasive species to adapt to new conditions may be enhanced.

scholarly journals Phenotypic and Genotypic Characterization of Escherichia coli Isolated from Untreated Surface Waters

2013 ◽  
Vol 7 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Kristopher J Janezic ◽  
Blake Ferry ◽  
Eric W Hendricks ◽  
Brian A Janiga ◽  
Tiffany Johnson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Surface Waters ◽  
Antimicrobial Agents ◽  
Genotypic Variation ◽  
Virulence Gene ◽  
Genotypic Diversity ◽  
Housekeeping Gene ◽  
Polymyxin B ◽  
Fecal Coliforms ◽  
E Coli

A common member of the intestinal microbiota in humans and animals isEscherichia coli. Based on the presence of virulence factors,E. colican be potentially pathogenic. The focus of this study was to isolateE. colifrom untreated surface waters (37 sites) in Illinois and Missouri and determine phenotypic and genotypic diversity among isolates. Water samples positive for fecal coliforms based on the Colisure®test were streaked directly onto Eosin Methylene Blue (EMB) agar (37°C) or transferred to EC broth (44.5°C). EC broth cultures producing gas were then streaked onto EMB agar. Forty-five isolates were identified asE. coliusing API 20E and Enterotube II identification systems, and some phenotypic variation was observed in metabolism and fermentation. Antibiotic susceptibility of each isolate was also determined using the Kirby-Bauer Method. Differential responses to 10 antimicrobial agents were seen with 7, 16, 2, and 9 of the isolates resistant to ampicillin, cephalothin, tetracycline, and triple sulfonamide, respectively. All of the isolates were susceptible or intermediate to amoxicillin, ciprofloxacin, polymyxin B, gentamicin, imipenem, and nalidixic acid. Genotypic variation was assessed through multiplex Polymerase Chain Reaction for four virulence genes (stx1andstx2[shiga toxin],eaeA[intimin]; andhlyA[enterohemolysin]) and one housekeeping gene (uidA[β-D-glucuronidase]). Genotypic variation was observed with two of the isolates possessing the virulence gene (eaeA) for intimin. These findings increase our understanding of the diversity ofE. coliin the environment which will ultimately help in the assessment of this organism and its role in public health.

An introduced pentastomid parasite (Raillietiella frenata) infects native cane toads (Rhinella marina) in Panama

Parasitology ◽  
2014 ◽  
Vol 142 (5) ◽  
pp. 675-679 ◽  
Author(s):  
CRYSTAL KELEHEAR ◽  
KRISTIN SALTONSTALL ◽  
MARK E. TORCHIN
Keyword(s):  
Central America ◽  
First Record ◽  
Host Shift ◽  
Native Range ◽  
Host Switch ◽  
Rhinella Marina ◽  
Introduced Populations ◽  
A Site ◽  
Hemidactylus Frenatus

SUMMARYThe pentastomid parasite, Raillietiella frenata, is native to Asia where it infects the Asian House gecko, Hemidactylus frenatus. This gecko has been widely introduced and recently R. frenata was found in introduced populations of cane toads (Rhinella marina) in Australia, indicating a host-switch from introduced geckos to toads. Here we report non-native adult R. frenata infecting the lungs of native cane toads in Panama. Eight of 64 toads were infected (median = 2·5, range = 1–80 pentastomids/toad) and pentastomid prevalence was positively associated with the number of buildings at a site, though further sampling is needed to confirm this pattern. We postulate that this pattern is likely due to a host shift of this parasite from an urban-associated introduced gecko. This is the first record of this parasite infecting cane toads in their native range, and the first instance of this parasite occurring in Central America.

scholarly journals Population Structure of Fusarium fujikuroi from California Rice and Water Grass

2008 ◽  
Vol 98 (9) ◽  
pp. 992-998 ◽  
Author(s):  
L. L. A. Carter ◽  
J. F. Leslie ◽  
R. K. Webster
Keyword(s):  
Population Structure ◽  
Fragment Length Polymorphism ◽  
Genotypic Variation ◽  
Genotypic Diversity ◽  
Population Diversity ◽  
Fusarium Fujikuroi ◽  
Mating Types ◽  
Bakanae Disease ◽  
Barnyard Grass ◽  
Vegetative Compatibility Groups

The recent observance of Fusarium fujikuroi, the causal agent of Bakanae disease of rice, in California provides a unique opportunity to assess the population diversity of an introduced pathogen in a new environment. We collected 172 isolates of this pathogen between 2000 and 2003 from California rice and two from water grass (Echinochloa spp.). Pathogenicity of F. fujikuroi was demonstrated on early water grass (E. oryzoides) and barnyard grass (E. crus-galli) indicating that weed control should be part of Bakanae management programs. Both mating types and six unique amplified fragment length polymorphism haplotypes corresponding to six identified vegetative compatibility groups were detected. The two most frequently isolated haplotypes encompassed 94% of the collected isolates, suggesting that clonal reproduction dominates. Coefficients of similarity between the unique haplotypes ranged from 0.94 to 0.98, and indicate that there is very little genotypic variation in the F. fujikuroi population in California. The near fixation of the MAT-1 idiomorph (observed ratio 170 MAT-1:4 MAT-2), is consistent with a hypothesis of predominant or exclusive asexual reproduction. The low level of introduced genotypic diversity, in conjunction with the asexual reproductive strategy of this population will slow evolutionary processes, including adaptation to the California environment.

scholarly journals Plant genotypic diversity increases population size of a herbivorous insect

2011 ◽  
Vol 278 (1721) ◽  
pp. 3108-3115 ◽  
Author(s):  
Shunsuke Utsumi ◽  
Yoshino Ando ◽  
Timothy P. Craig ◽  
Takayuki Ohgushi
Keyword(s):  
Population Dynamics ◽  
Population Size ◽  
Natural Enemy ◽  
Genotypic Variation ◽  
Genotypic Diversity ◽  
Community Genetics ◽  
Aphid Population ◽  
Herbivorous Insect ◽  
Mixed Genotype ◽  
The Impact

It is critical to incorporate the process of population dynamics into community genetics studies to identify the mechanisms of the linkage between host plant genetics and associated communities. We studied the effects of plant genotypic diversity of tall goldenrod Solidago altissima on the population dynamics of the aphid Uroleucon nigrotuberculatum . We found genotypic variation in plant resistance to the aphid in our experiments. To determine the impact of plant genotypic diversity on aphid population dynamics, we compared aphid densities under conditions of three treatments: single-genotype plots, mixed-genotype plots and mixed-genotype-with-cages plots. In the latter treatment plants were individually caged to prevent natural enemy attack and aphid movement among plants. The synergistic effects of genotypes on population size were demonstrated by the greater aphid population size in the mixed-genotype treatment than expected from additive effects alone. Two non-exclusive hypotheses are proposed to explain this pattern. First, there is a source–sink relationship among plant genotypes: aphids move from plant genotypes where their reproduction is high to genotypes where their reproduction is low. Second, natural enemy mortality is reduced in mixed plots in a matrix of diverse plant genotypes.

scholarly journals Genotypic variation in a foundation tree ( Populus tremula L.) explains community structure of associated epiphytes

2014 ◽  
Vol 10 (4) ◽  
pp. 20140190 ◽  
Author(s):  
Chantel Davies ◽  
Christopher J. Ellis ◽  
Glenn R. Iason ◽  
Richard A. Ennos
Keyword(s):  
Community Structure ◽  
Environmental Conditions ◽  
Spatial Scales ◽  
Genotypic Variation ◽  
Genotypic Diversity ◽  
Environmental Variation ◽  
Populus Tremula ◽  
Foundation Species ◽  
Community Genetics ◽  
Epiphyte Community

Community genetics hypothesizes that within a foundation species, the genotype of an individual significantly influences the assemblage of dependent organisms. To assess whether these intra-specific genetic effects are ecologically important, it is required to compare their impact on dependent organisms with that attributable to environmental variation experienced over relevant spatial scales. We assessed bark epiphytes on 27 aspen ( Populus tremula L.) genotypes grown in a randomized experimental array at two contrasting sites spanning the environmental conditions from which the aspen genotypes were collected. We found that variation in aspen genotype significantly influenced bark epiphyte community composition, and to the same degree as environmental variation between the test sites. We conclude that maintaining genotypic diversity of foundation species may be crucial for conservation of associated biodiversity.

scholarly journals Genetic variation for photosynthetic capacity and efficiency in spring wheat

2019 ◽  
Vol 71 (7) ◽  
pp. 2299-2311 ◽  
Author(s):  
Viridiana Silva-Pérez ◽  
Joanne De Faveri ◽  
Gemma Molero ◽  
David M Deery ◽  
Anthony G Condon ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Stomatal Conductance ◽  
Photosynthetic Capacity ◽  
Genotypic Variation ◽  
Genotypic Diversity ◽  
Dry Mass ◽  
Co2 Assimilation ◽  
Leaf Nitrogen ◽  
Yield Potential

Abstract One way to increase yield potential in wheat is screening for natural variation in photosynthesis. This study uses measured and modelled physiological parameters to explore genotypic diversity in photosynthetic capacity (Pc, Rubisco carboxylation capacity per unit leaf area at 25 °C) and efficiency (Peff, Pc per unit of leaf nitrogen) in wheat in relation to fertilizer, plant stage, and environment. Four experiments (Aus1, Aus2, Aus3, and Mex1) were carried out with diverse wheat collections to investigate genetic variation for Rubisco capacity (Vcmax25), electron transport rate (J), CO2 assimilation rate, stomatal conductance, and complementary plant functional traits: leaf nitrogen, leaf dry mass per unit area, and SPAD. Genotypes for Aus1 and Aus2 were grown in the glasshouse with two fertilizer levels. Genotypes for Aus3 and Mex1 experiments were grown in the field in Australia and Mexico, respectively. Results showed that Vcmax25 derived from gas exchange measurements is a robust parameter that does not depend on stomatal conductance and was positively correlated with Rubisco content measured in vitro. There was significant genotypic variation in most of the experiments for Pc and Peff. Heritability of Pc reached 0.7 and 0.9 for SPAD. Genotypic variation and heritability of traits show that there is scope for these traits to be used in pre-breeding programmes to improve photosynthesis with the ultimate objective of raising yield potential.

Genotyping Puccinia striiformis f. sp. tritici Isolates with SSR and SP-SNP Markers Reveals Dynamics of the Wheat Stripe Rust Pathogen in the United States from 1968 to 2009 and Identifies Avirulence Associated Markers

2021 ◽  
Author(s):  
Tinglan Liu ◽  
Qing Bai ◽  
Meinan Wang ◽  
Yuxiang Li ◽  
Anmin Wan ◽  
...  
Keyword(s):  
United States ◽  
Stripe Rust ◽  
Puccinia Striiformis ◽  
Genetic Relationships ◽  
Genotypic Diversity ◽  
The United States ◽  
Snp Markers ◽  
Avirulence Genes ◽  
Introduced Populations ◽  
The Us

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a devastating disease of wheat in the United States. The fungal pathogen can rapidly evolve, producing new virulent races infecting previously resistant cultivars and genotypes adapting to different environments. The objective of this study was to investigate the long-term population dynamics of Pst in the US. Through genotyping 1,083 isolates of 1968 to 2009 using 14 simple sequence repeat (SSR) markers and 92 secreted protein single nucleotide polymorphism (SP-SNP) markers, 614 and 945 genotypes were detected, respectively. In general, the two types of markers produced consistent genetic relationships among the Pst populations over the 40 years. The prior 2000 and 2000-2009 populations were significantly different, and the latter showed higher genotypic diversity and higher heterozygosity than the former populations. Clustering analyses using genotypes of either SSR and SP-SNP markers revealed three molecular groups (MGs), of which MG1 and MG2 existed in both the prior 2000 and 2000-2009 populations while MG3 mainly emerged in 2000 to 2009. Some of the isolates in the period of 2000-2009 formed individual clusters, suggesting exotic incursions; whereas other isolates of the same period were clustered together with prior-2000 isolates, indicating that they were developed from the previously established populations. The data suggest the co-existence of newly introduced populations with established populations in the United States. Twenty SP-SNP markers were significantly associated to individual avirulence genes. The results are useful for developing more accurate monitoring systems and provides guidance for the disease management.

Parasites and marine invasions

Parasitology ◽  
2002 ◽  
Vol 124 (7) ◽  
pp. 137-151 ◽  
Author(s):  
M. E. TORCHIN ◽  
K. D. LAFFERTY ◽  
A. M. KURIS
Keyword(s):  
Invasive Species ◽  
Marine Species ◽  
Economic Problem ◽  
Invasion Success ◽  
Native Range ◽  
Marine Systems ◽  
Introduced Populations ◽  
Marine Invasions ◽  
Introduced Range ◽  
Marine Parasites

Introduced marine species are a major environmental and economic problem. The rate of these biological invasions has substantially increased in recent years due to the globalization of the world's economies. The damage caused by invasive species is often a result of the higher densities and larger sizes they attain compared to where they are native. A prominent hypothesis explaining the success of introduced species is that they are relatively free of the effects of natural enemies. Most notably, they may encounter fewer parasites in their introduced range compared to their native range. Parasites are ubiquitous and pervasive in marine systems, yet their role in marine invasions is relatively unexplored. Although data on parasites of marine organisms exist, the extent to which parasites can mediate marine invasions, or the extent to which invasive parasites and pathogens are responsible for infecting or potentially decimating native marine species have not been examined. In this review, we present a theoretical framework to model invasion success and examine the evidence for a relationship between parasite presence and the success of introduced marine species. For this, we compare the prevalence and species richness of parasites in several introduced populations of marine species with populations where they are native. We also discuss the potential impacts of introduced marine parasites on native ecosystems.

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