scholarly journals Invasion genomics uncover contrasting scenarios of genetic diversity in a widespread marine invader

2021 ◽  
Vol 118 (51) ◽  
pp. e2116211118
Author(s):  
Cornelia Jaspers ◽  
Moritz Ehrlich ◽  
José Martin Pujolar ◽  
Sven Künzel ◽  
Till Bayer ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Propagule Pressure ◽  
Invasion Success ◽  
Invasion Dynamics ◽  
The Past ◽  
Marine Invasive Species ◽  
Successful Establishment ◽  
Low Levels ◽  
International Conventions ◽  
Dominant Paradigm

Invasion rates have increased in the past 100 y irrespective of international conventions. What characterizes a successful invasion event? And how does genetic diversity translate into invasion success? Employing a whole-genome perspective using one of the most successful marine invasive species world-wide as a model, we resolve temporal invasion dynamics during independent invasion events in Eurasia. We reveal complex regionally independent invasion histories including cases of recurrent translocations, time-limited translocations, and stepping-stone range expansions with severe bottlenecks within the same species. Irrespective of these different invasion dynamics, which lead to contrasting patterns of genetic diversity, all nonindigenous populations are similarly successful. This illustrates that genetic diversity, per se, is not necessarily the driving force behind invasion success. Other factors such as propagule pressure and repeated introductions are an important contribution to facilitate successful invasions. This calls into question the dominant paradigm of the genetic paradox of invasions, i.e., the successful establishment of nonindigenous populations with low levels of genetic diversity.

Invasion Success in Cogongrass (Imperata cylindrica): A Population Genetic Approach Exploring Genetic Diversity and Historical Introductions

2014 ◽  
Vol 7 (1) ◽  
pp. 59-75 ◽  
Author(s):  
Rima D. Lucardi ◽  
Lisa E. Wallace ◽  
Gary N. Ervin
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Biological Invasion ◽  
Propagule Pressure ◽  
Gulf Coast ◽  
The United States ◽  
Parent Material ◽  
Imperata Cylindrica ◽  
Invasion Success ◽  
Grass Species

AbstractPropagule pressure significantly contributes to and limits the potential success of a biological invasion, especially during transport, introduction, and establishment. Events such as multiple introductions of foreign parent material and gene flow among them can increase genetic diversity in founding populations, often leading to greater invasion success. We applied the tools and theory of population genetics to better understand the dynamics of successful biological invasion. The focal species, cogongrass, is a perennial invasive grass species significantly affecting the Gulf Coast and southeastern region of the United States. The literature indicates separate, allopatric introductions of material from East Asia (Philippines and Japan) into the U.S. states of Mississippi and Alabama. Molecular analysis of samples from those two states utilized amplified fragment length polymorphism (AFLP) markers on 388 individuals from 21 localities. We hypothesized that previously isolated lineages of cogongrass are present and crossing in the Southeast. We observed genetic variation within localities (0.013 ≤ heterozygosity (He) ≤ 0.051, mean = 0.028 ± 0.001) with significant and substantial population structure (FST= 0.534, P < 0.001). Population structure analyses detected two genetically defined and statistically supported populations, which appear to have experienced some admixture. The geographic distribution of those populations was consistent with the two-introduction scenario reported previously. These results are also consistent with contact in the invasive range of previously isolated lineages from the native range.

scholarly journals Analysis of propagule pressure and genetic diversity in the invasibility of a freshwater apex predator: the peacock bass (genus Cichla)

2014 ◽  
Vol 12 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Daniel C. Carvalho ◽  
Denise A. A. Oliveira ◽  
Iracilda Sampaio ◽  
Luciano B. Beheregaray
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Amazon Basin ◽  
Biotic Resistance ◽  
Propagule Pressure ◽  
Invasion Success ◽  
Southeastern Brazil ◽  
Feeding Strategies ◽  
Apex Predator ◽  
Biological Variables

An important step in invasive biology is to assess biological variables that could be used to predict invasion success. The study of genetics, evolution, and interactions of invasive and native species in invaded ranges provides a unique opportunity to study processes in population genetics and the capability of a species' range expansion. Here, we used information from microsatellite DNA markers to test if genetic variation relates to propagule pressure in the successful invasion of an apex predator (the Amazonian cichlid Cichla) into Southeastern Brazilian River systems. Invasive populations of Cichla have negatively impacted many freshwater communities in Southeastern Brazil since the 1960s. Reduction of genetic variation was observed in all invasive populations for both Cichla kelberi (CK) and Cichla piquiti(CP). For instance, heterozygosity was lower in the invasive range when compared to native populations from the Amazon basin (CP HE= 0.179/0.44; CK HE= 0.258/0.536 respectively). Therefore, despite the successful invasion of Cichla in southeast Brazil, low genetic diversity was observed in the introduced populations. We suggest that a combination of factors, such as Cichla's reproductive and feeding strategies, the "evolutionary trap" effect and the biotic resistance hypothesis, overcome their depauperete genetic diversity, being key aspects in this apex predator invasion.

scholarly journals Genetic variation in lowland and mountain populations of Tofieldia calyculata and their ability to survive within low levels of genetic diversity

2021 ◽  
Author(s):  
Tomáš Vlasta ◽  
Zuzana Műnzbergová
Keyword(s):  
Genetic Diversity ◽  
Suitable Habitat ◽  
Herbarium Specimens ◽  
The Past ◽  
Low Genetic Diversity ◽  
Genetic Diversity And Structure ◽  
Population Sizes ◽  
Range Periphery ◽  
Low Levels ◽  
European Mountains

Abstract Loss of genetic diversity is expected to be a common reason for decline of populations of many rare species. To what extent this is true for populations at the range periphery remains to be explored. Alpine species with peripheral lowland populations are ideal but poorly known model system to address this issue. We investigated genetic diversity and structure of populations of Tofieldia calyculata, species common in central European mountains but highly endangered in lowlands using 17 microsatellite loci. We showed that lowland populations have lower genetic diversity than mountain populations and they are not clearly differentiated from mountain populations. Species probably survived the last glaciation in refugia in margins of Alps and western Carpathians. Some lowland populations are probably relict as well and contain unique genetic information. Their low genetic diversity is likely the result the of reduction of population sizes, gene flow during the Holocene and selfing. However postglacial colonization is also a case of some lowland populations. Based on data from herbarium specimens from extinct lowland populations, we demonstrated that lowland populations had low genetic diversity also in the past and main part of the genetic diversity was lost due to extinction of whole populations. Within population genetic diversity has not changed since the last century suggesting that these populations are able to survive with low levels of genetic diversity under suitable habitat conditions. This idea is also supported by finding of large viable recent populations with very low genetic diversity. We conclude that lowland populations are unique and deserve adequate conservation.

A KUHNIAN INTERPRETATION OF THE HISTORICAL EVOLUTION OF ACCOUNTING

1989 ◽  
Vol 16 (2) ◽  
pp. 1-41 ◽  
Author(s):  
Barry E. Cushing
Keyword(s):  
Historical Evolution ◽  
Scientific Revolutions ◽  
The Past ◽  
Structure Of Scientific Revolutions ◽  
Model Following ◽  
Entry Model ◽  
Scientific Disciplines ◽  
Uncertain Future ◽  
Double Entry ◽  
Dominant Paradigm

Distinct parallels exist between the historical evolution of scientific disciplines, as explained in Thomas Kuhn's The Structure of Scientific Revolutions, and the historical evolution of the accounting discipline. These parallels become apparent when accounting's dominant paradigm is interpreted to be the double-entry bookkeeping model. Following this interpretation, the extensive articulation of the double-entry model over the past four centuries may be seen to closely resemble the “normal science” of Kuhn's theory. Further parallels become apparent when Kuhn's concept of the disciplinary crises that precede scientific revolutions is compared to developments in the accounting discipline over the past 25 years. This portrayal of accounting's evolution suggests an uncertain future for the accounting discipline.

scholarly journals The emergence of coercive federal Australian labour law, 1901–2020

2021 ◽  
pp. 002218562110039
Author(s):  
Eugene Schofield-Georgeson
Keyword(s):  
Industrial Relations ◽  
High Volume ◽  
Union Power ◽  
Labour Law ◽  
Industrial Environment ◽  
The Past ◽  
Low Levels ◽  
Labour Legislation ◽  
Employment Legislation

Over the past two decades, industrial relations scholarship has observed a trend towards an increasingly punitive industrial environment along with the ‘re-regulation’ of labour law. Absent from much of this literature, however, has been an empirical and historical measurement or comparison of the scale and quality of this systemic change. By surveying coercive and penal federal industrial legislation over the period 1901–2020, this study shows empirically that over the last 40 years, there has been a steep increase in the amount of coercive federal labour legislation in Australia. It further measures and compares the volume of coercive labour legislation enacted specifically against ‘labour’ and ‘capital’ or both throughout the same period (1901–2020). Analysis reveals a correlation between a high volume of coercive labour legislation with low levels of trade union power and organisation. Argued here is that coercive labour legislation has been crucial to transitioning from a liberal conciliation and arbitration model of Australian industrial relations towards a neoliberal framework of employment legislation. In the former, regulation was more collective, informal and egalitarian (embodied by the sociological concept of ‘associative democracy’). Under a neoliberal framework, regulation is now more individualised, technical, punitive and rarely enforced, resulting in less equal material outcomes.

scholarly journals Genetic Diversity of Spiroplasma citri Strains from Different Regions, Hosts, and Isolation Dates

2008 ◽  
Vol 98 (9) ◽  
pp. 960-968 ◽  
Author(s):  
A. F. S. Mello ◽  
R. K. Yokomi ◽  
U. Melcher ◽  
J. C. Chen ◽  
A. C. Wayadande ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Collection Site ◽  
Spiroplasma Citri ◽  
The Past ◽  
Rapd Pcr ◽  
Membrane Lipoprotein ◽  
Polymerase Chain ◽  
Multiple Strains ◽  
Genetic Signatures ◽  
Random Amplified Polymorphism Dna

Spiroplasma citri, a phloem-limited pathogen, causes citrus stubborn disease (CSD). Losses due to CSD in California orchards have grown over the past decade. To investigate the possibility of introduction or emergence of a new strain, a study of genetic diversity among S. citri strains from various locations was conducted using random amplified polymorphism DNA-polymerase chain reaction (RAPD-PCR) of 35 strains cultured from 1980 to 1993, and of 35 strains cultured from 2005 to 2006. Analysis using 20 primer pairs revealed considerable diversity among strains. However, no unique genetic signatures were associated with recently collected strains compared with those collected 15 to 28 years ago, and no geographically associated pattern was distinguishable. S. citri strains from carrot and daikon radish contain some unique DNA fragments, suggesting some host plant influence. Multiple strains from single trees also showed genetic diversity. Sequencing of five RAPD bands that differed among strains showed that diversity-related gene sequences include virus fragments, and fragments potentially encoding a membrane lipoprotein, a DNA modification enzyme, and a mobilization element. No differences in colony morphology were observed among the strains. The lack of correlation between PCR patterns and isolation date or collection site is inconsistent with the hypothesis that recent infections are due to the introduction or emergence of novel pathogen strains.

Breeding and Mating Systems of Australian Proteaceae

1998 ◽  
Vol 46 (4) ◽  
pp. 421 ◽  
Author(s):  
Ross L. Goldingay ◽  
Susan M. Carthew
Keyword(s):  
Fruit Development ◽  
Mating Systems ◽  
Pollen Deposition ◽  
Genetic Studies ◽  
The Past ◽  
Wide Range ◽  
The Family ◽  
Self Compatibility ◽  
Low Levels ◽  
Key Events

There has been a significant increase in the number of studies investigating plant breeding and mating systems over the past 10 years. The family Proteaceae, in particular, has dominated such research conducted in Australia. Thus it is now timely to present a critical review of the breeding and mating systems of the Australian Proteaceae. It is hoped that this will stimulate further research. The review covers key events between pollen deposition on stigmas through to fruit set. The genus Banksia, although not the most diverse of the family, has received a disproportionate amount of attention. It has featured in nine published studies of self-compatibility compared to 13 studies spanning the other 45 genera and has featured in eight genetic studies of the mating system compared to just two on other genera. Few studies have assessed the timing of stigma receptivity despite the intriguing situation in most Proteaceae of auto-deposition of self-pollen on or near stigmas at anthesis. Studies suggest that stigmas are not receptive until 0.5–4 days after anthesis. Banksia species appear to show low levels of self-compatibility although one subspecies shows high levels of selfing and evidence of selective fruit development. Self-compatibility may be more common in other genera, although a dearth of studies precludes generalisation. Assessment of mating systems indicates almost complete outcrossing for most species, lending support to the idea of selective fruit development. It is clear that many further studies of all topics are required but particularly across a wide range of genera because many have not been studied at all.

scholarly journals Genetic diversity of rice stem borer (Chilo suppressalis Walker) from Northern Iran and comparison with other countries

2016 ◽  
Vol 48 (3) ◽  
pp. 360 ◽  
Author(s):  
M. Shayanmehr ◽  
E. Yoosefi-Lafooraki
Keyword(s):  
Genetic Diversity ◽  
Stem Borer ◽  
Chilo Suppressalis ◽  
Mazandaran Province ◽  
Northern Iran ◽  
Low Genetic Diversity ◽  
High Gene ◽  
Major Pest ◽  
Different Populations ◽  
Low Levels

Rice striped stem borer, <em>Chilo suppressalis</em> Walker (Lepidoptera: Crambidae) is considered the major pest of rice in Iran. Because of the serious damage on rice in Northern Iran, the present study was conducted to investigate genetic diversity within populations of <em>C. suppressalis</em>, from Mazandaran using a template of cytochrome oxidase I gene, 750 bps, (<em>COI</em>). Later the haplotypes from Iran were compared with those found in other countries. According to the results of this study, there is very low genetic diversity (two haplotypes) among different populations of this pest in populations of Northern Iran. The genetic similarity and low levels of genetic diversity of these populations suggest that the pest colonization occurred relatively recently and there is high gene flow between these populations of the province. In addition, haplotypes of Mazandaran province are different with those found in other countries. The similarity of Iranian population (Simorgh) with one population from China indicated that China might be the origin of <em>C. suppresalis</em>.

scholarly journals Enhancing (crop) plant photosynthesis by introducing novel genetic diversity

2017 ◽  
Vol 372 (1730) ◽  
pp. 20160380 ◽  
Author(s):  
Marcel Dann ◽  
Dario Leister
Keyword(s):  
Genetic Diversity ◽  
Genetic Manipulation ◽  
Plant Evolution ◽  
Crop Plants ◽  
Crop Plant ◽  
Higher Plant ◽  
Novel Approach ◽  
Population Sizes ◽  
Plant Photosynthesis ◽  
Successful Establishment

Although some elements of the photosynthetic light reactions might appear to be ideal, the overall efficiency of light conversion to biomass has not been optimized during evolution. Because crop plants are depleted of genetic diversity for photosynthesis, efforts to enhance its efficiency with respect to light conversion to yield must generate new variation. In principle, three sources of natural variation are available: (i) rare diversity within extant higher plant species, (ii) photosynthetic variants from algae, and (iii) reconstruction of no longer extant types of plant photosynthesis. Here, we argue for a novel approach that outsources crop photosynthesis to a cyanobacterium that is amenable to adaptive evolution. This system offers numerous advantages, including a short generation time, virtually unlimited population sizes and high mutation rates, together with a versatile toolbox for genetic manipulation. On such a synthetic bacterial platform, 10 000 years of (crop) plant evolution can be recapitulated within weeks. Limitations of this system arise from its unicellular nature, which cannot reproduce all aspects of crop photosynthesis. But successful establishment of such a bacterial host for crop photosynthesis promises not only to enhance the performance of eukaryotic photosynthesis but will also reveal novel facets of the molecular basis of photosynthetic flexibility. This article is part of the themed issue ‘Enhancing photosynthesis in crop plants: targets for improvement’.

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