scholarly journals Patterns of Genetic Diversity in Highly Invasive Species: Cogongrass (Imperata cylindrica) Expansion in the Invaded Range of the Southern United States (US)

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 423 ◽  
Author(s):  
Rima D. Lucardi ◽  
Lisa E. Wallace ◽  
Gary N. Ervin
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Invasive Species ◽  
Imperata Cylindrica ◽  
Southern United States ◽  
Genetic Lineage ◽  
Us States ◽  
Genetic Lineages ◽  
Genetic Diversity And Structure ◽  
Pinus Spp

The spatial expansions of invasive organisms in the novel range are generally expected to follow an isolation-by-distance relationship (IBD) if the invasion is biologically driven; however, many invasions are facilitated anthropogenically. This research focused on the extant expansion patterns of cogongrass (Imperata cylindrica). Cogongrass is a widespread invasive species throughout the southern United States (US). Patterns of infestation vary among US states. Cogongrass is pyrogenic, and its invasion threatens softwood (Pinus spp.) plantations, a substantial economic market for this US region. Over 600 individuals were sampled from seven invaded US states, using amplified fragment length polymorphisms (AFLPs) to assess genetic diversity and population structure. We suspected that differences in historical management efforts among US states influenced differences in genetic diversity and structure. We detected two genetic lineages at the highest level of analysis. One genetic lineage was locally restricted, whereas the other was found throughout the study region. Admixed individuals were found in all US states and consistently co-occurred with the dominant lineage, suggesting that secondary contact and hybridization may have facilitated expansion. The widespread prevalence of only one of the two detected genetic lineages suggests a primary genetic lineage responsible for on-going population expansion in the US.

scholarly journals Genetic diversity and structure of the narrow endemic Seseli farrenyi (Apiaceae): implications for translocation

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10521
Author(s):  
Núria Garcia-Jacas ◽  
Jèssica Requena ◽  
Sergi Massó ◽  
Roser Vilatersana ◽  
Cèsar Blanché ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Decline ◽  
Natural Populations ◽  
Ex Situ ◽  
Endemic Plant ◽  
Genetic Lineages ◽  
Narrow Endemic ◽  
Management Measures ◽  
Genetic Diversity And Structure ◽  
Nw Mediterranean

Seseli farrenyi (Apiaceae) is an extremely narrow endemic plant, which is considered as one of the species of most conservation concern in Catalonia (NW Mediterranean Basin). Given the accelerated fragmentation and reduction of population size (of over 90%), the environmental agency of Catalonia is currently preparing a recovery plan that includes reinforcements of the extant populations. The present study is aimed at providing the necessary knowledge to carry out genetically-informed translocations, by using microsatellites as genetic markers. Fourteen microsatellites have been specifically developed for S. farrenyi, of which nine have been used. Besides the extant natural populations, the three ex situ collections that are known to exist of this species have also been studied, as they would be the donor sources for translocation activities. Our main finding is that levels of genetic diversity in the natural populations of S. farrenyi are still high (He = 0.605), most likely as a result of a predominantly outcrossing mating system in combination with the limited time elapsed since the population decline. However, population fragmentation is showing the first genetic signs, as the values of genetic differentiation are relatively high, and two well-differentiated genetic lineages have been found even in such a narrow geographic range. These genetic results provide important information when designing conservation management measures.

scholarly journals Correlates of non-random patterns of capsule switching in pneumococcus

2019 ◽  
Author(s):  
Shreyas S. Joshi ◽  
M. A. Al-Mamun ◽  
Daniel M. Weinberger
Keyword(s):  
Genetic Diversity ◽  
Genetic Background ◽  
Regression Models ◽  
Glucuronic Acid ◽  
Genetic Lineage ◽  
Structural Components ◽  
Genetic Lineages ◽  
Polysaccharide Capsule ◽  
Random Patterns ◽  
The Relationship

ABSTRACTBackgroundPneumococcus is a diverse pathogen, with >90 serotypes, each of which has a distinct polysaccharide capsule. Pneumococci can switch capsules, evading vaccine pressure. Certain serotype pairs are more likely to switch, but the drivers of these patterns are not well understood.MethodsWe used the PubMLST and Global Pneumococcal Sequencing (GPS) databases to quantify the number of genetic lineages on which different serotype pairs co-occur. We also quantified the genetic diversity of each serotype. Regression models evaluated the relationship between shared polysaccharide structural components and the frequency of serotype switching and diversity.ResultsA number of serotype pairs co-occurred on the same genetic lineage more commonly than expected. Co-occurrence of between-serogroup pairs was more common when both serotypes had glucose as a component of the capsule (and, potentially, glucuronic acid). Diversity also varied markedly by serotype and was lower for serotypes with glucuronic acid in the capsule and higher for those with galactose in the capsule.ConclusionsCertain pairs of serotypes are more likely to occur on the same genetic background, and these patterns were correlated with shared polysaccharide components. This might indicate adaptation of strains to produce capsules with particular characteristics.

High genetic diversity in the clonal aquatic weed Alternanthera philoxeroides in the United States

2020 ◽  
pp. 1-9
Author(s):  
Dean A. Williams ◽  
Nathan E. Harms ◽  
Ian A. Knight ◽  
Brenda J. Grewell ◽  
Caryn Joy Futrell ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Biological Control ◽  
Haplotype Diversity ◽  
Genetic Data ◽  
The United States ◽  
Control Measures ◽  
Alternanthera Philoxeroides ◽  
Southern United States ◽  
Aquatic Weed

Abstract The distribution of genetic diversity in invasive plant populations can have important management implications. Alligatorweed [Alternanthera philoxeroides (Mart.) Griseb.] was introduced into the United States around 1900 and has since spread throughout much of the southern United States and California. A successful biological control program was initiated in the late 1960s that reduced A. philoxeroides in the southern United States, although control has varied geographically. The degree to which variation among genotypes may be responsible for variation in control efficacy has not been well studied due to a lack of genetic data. We sampled 373 plants from 90 sites across the United States and genotyped all samples at three chloroplast regions to help inform future management efforts. Consistent with clonal spread, there was high differentiation between sites, yet we found six haplotypes and high haplotype diversity (mean h = 0.48) across states, suggesting this plant has been introduced multiple times. Two of the haplotypes correspond to previously described biotypes that differ in their susceptibility to herbicides and herbivory. The geographic distribution of the three common haplotypes varied by latitude and longitude, while the other haplotypes were widespread or localized to one or a few sites. All the haplotypes we screened are hexaploid (6n = 102), which may enhance biological control. Future studies can use these genetic data to determine whether genotypes differ in their invasiveness or respond differently to control measures. Some states, for instance, have mainly a single haplotype that may respond more uniformly to a single control strategy, whereas other states may require a variety of control strategies. These data will also provide the basis for identifying the source regions in South America, which may lead to the discovery of new biological control agents more closely matched to particular genotypes.

scholarly journals Population Structure of the Blueberry Pathogen Monilinia vaccinii-corymbosi in the United States

2015 ◽  
Vol 105 (4) ◽  
pp. 533-541 ◽  
Author(s):  
Kathleen M. Burchhardt ◽  
Marc A. Cubeta
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
New York ◽  
Population Structure ◽  
Population Biology ◽  
Random Mating ◽  
The United States ◽  
Restricted Gene Flow ◽  
Southeast United States ◽  
Genetic Diversity And Structure

The fungus Monilinia vaccinii-corymbosi causes disease of blueberry (Vaccinium section Cyanococcus) shoots, flowers, and fruit. The objective of our research was to examine the population biology and genetics of M. vaccinii-corymbosi in the United States. A total of 480 samples of M. vaccinii-corymbosi were collected from 18 blueberry fields in 10 states; one field in Georgia, Massachusetts, Maine, Michigan, Mississippi, New Jersey, New York, Oregon, and Washington and nine fields in North Carolina. Analysis with 10 microsatellite markers revealed 247 unique multilocus haplotypes (MLHs), with 244 MLHs detected within 11 fields in the Northeast, Northwest, Midwest, and Southeast and three MLHs detected within seven fields in the Southeast United States. Genetic similarity and low genetic diversity of M. vaccinii-corymbosi isolates from the seven fields in the Southeast United States suggested the presence of an expansive, self-fertile population. Tests for linkage disequilibrium within 10 fields that contained ≥12 MLHs supported random mating in six fields and possible inbreeding and/or self-fertilization in four fields. Analysis of molecular variance, discriminate analysis of principal components, and Bayesian cluster analysis provided evidence for population structure and restricted gene flow among fields. This research represents the first comprehensive investigation of the genetic diversity and structure of field populations of M. vaccinii-corymbosi.

scholarly journals Genetic Diversity and Conservation Status of Helianthus verticillatus, an Endangered Sunflower of the Southern United States

2020 ◽  
Vol 11 ◽  
Author(s):  
Tyler P. Edwards ◽  
Robert N. Trigiano ◽  
Bonnie H. Ownley ◽  
Alan S. Windham ◽  
Christopher R. Wyman ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Conservation Status ◽  
Southern United States

scholarly journals Genetic Diversity and Structure of the Apiosporina morbosa Populations on Prunus spp.

2005 ◽  
Vol 95 (8) ◽  
pp. 859-866 ◽  
Author(s):  
Jinxiu Zhang ◽  
W. G. Dilantha Fernando ◽  
William. R. Remphrey
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Gene Flow ◽  
Host Species ◽  
Population Differentiation ◽  
The United States ◽  
Flow Rates ◽  
Geographic Locations ◽  
Genetic Diversity And Structure ◽  
Geographic Populations

Populations of Apiosporina morbosa collected from 15 geographic locations in Canada and the United States and three host species, Prunus virginiana, P. pensylvanica, and P. padus, were evaluated using the sequence-related amplified polymorphism (SRAP) technique to determine their genetic diversity and population differentiation. Extensive diversity was detected in the A. morbosa populations, including 134 isolates from Canada and the United States, regardless of the origin of the population. The number of polymorphic loci varied from 6.9 to 82.8% in the geographic populations, and from 41.4 to 79.3% in the populations from four host genotypes based on 58 polymorphic fragments. In all, 44 to 100% of isolates in the geographic populations and 43.6 to 76.2% in populations from four host genotypes represented unique genotypes. Values of heterozygosity (H) varied from 2.8 to 28.3% in the geographic populations and 10.2 to 26.1% in the populations from four host genotypes. In general, the A. morbosa populations sampled from wild chokecherry showed a higher genetic diversity than those populations collected from other host species, whereas the populations isolated from cultivated chokecherry, P. virginiana ‘Shubert Select’, showed a reduction of genetic diversity compared with populations from wild P. virginiana. Significant population differentiation was found among both the geographic populations (P < 0.05) and populations from different host genotypes (P < 0.02). In the geographic populations, most of populations from cultivated and wild P. virginiana were closely clustered, and no population differentiation was detected except for the populations from Morris, Morden, and Winnipeg, Manitoba, Canada. Furthermore, the populations from P. virginiana in the same geographic locations had higher genetic identity and closer genetic distance to each other compared with those from different locations. Four populations from P. virginiana, P. pensylvanica, and P. padus, were significantly differentiated from each other (P < 0.02), except there was no differentiation between the Shubert Select and wild chokecherry populations (>P> = 0.334). Indirect estimation of gene flow showed that significant restricted gene flow existed between populations from different regions and host species. Gene flow rates (Nm) varied from <1 to 12.5, with higher gene flow rates among population pairs from the same host species (P = 1.000). The analysis of molecular variance revealed that a major genetic variance source came from the genetic variation among isolates within populations regardless of the origin and host genotype of the population. Although some locations had a limited number of isolates, the results of this study clearly showed that the genetic diversity and population differentiation of A. morbosa were closely associated with host genotypes and geographic locations, but mostly with the former.

scholarly journals Genetic diversity and structure of two species of Enyalius (Squamata: Leiosauridae) from neotropical biodiversity hotspots

2015 ◽  
Vol 14 (2) ◽  
pp. 99 ◽  
Author(s):  
Sarah M. Vargas ◽  
Marcelo De Oliveira Santos ◽  
Iara Alves Novelli ◽  
Celso Henrique Varela-Rios ◽  
Lúcio Moreira Campos Lima ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
South America ◽  
Genetic Distance ◽  
Population Variation ◽  
Published Data ◽  
Biodiversity Hotspots ◽  
Cryptic Diversity ◽  
Genetic Lineages ◽  
Genetic Diversity And Structure ◽  
First Time

Genetic diversity and structure of two species of Enyalius (Squamata: Leiosauridae) from neotropical biodiversity hotspots. Enyalius, a lizard genus endemic to South America, is mostly distributed in the remains of the Atlantic Forest and in the Cerrado. The genus has been the topic of a few studies but none has quantified the genetic diversity and structure within and among populations of Enyalius. The genetic diversity and structure of populations of E. bilineatus (N = 20) and E. perditus (N = 28) are examined using a 234-bp fragment of the cytochrome b gene and compared with the sequences reported in other published data. Nineteen distinct haplotypes (eleven for E. perditus and eight for E. bilineatus) were found, eight of which were recorded for the first time. The haplotype diversities are highly similar for both species (0.684 for E. perditus and 0.647 for E. bilineatus). The genetic distance between the two species is 20.3% and the distance within species is 2.0% and 5.6% for E. perditus and E. bilineatus, respectively. Our data suggest that populations of E. bilineatus are genetically divergent and may reveal cryptic diversity. This is the first study to quantify the genetic diversity of species of Enyalius from Neotropical biodiversity hotspots. These data facilitate a better understanding of both within and among population variation, and highlight the distribution of genetic lineages of an endemic and poorly studied genus.

Genetic Diversity of Cystodiscus Species in Amphibians in the Southern United States

10.1645/21-73 ◽  
2021 ◽  
Vol 107 (6) ◽  
Author(s):  
Christopher M. Whipps ◽  
Chris T. McAllister ◽  
K. Alice Lindsay
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Southern United States
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