scholarly journals Dynamics of the sex ratio in Tetrahymena thermophila

2018 ◽  
Author(s):  
Guangying Wang ◽  
Kai Chen ◽  
Jing Zhang ◽  
Xuefeng Ma ◽  
Shanjun Deng ◽  
...  
Keyword(s):  
Population Genetics ◽  
Sex Ratio ◽  
Mating Systems ◽  
Tetrahymena Thermophila ◽  
Mating Types ◽  
Eukaryotic Lineage ◽  
Single Sex ◽  
Theoretical Predictions ◽  
The Impact ◽  
Insight Into

AbstractSex is often hailed as one of the major successes in evolution, and in sexual organisms the maintenance of proper sex ratio is crucial. As a large unicellular eukaryotic lineage, ciliates exhibit tremendous variation in mating systems, especially the number of sexes and the mechanism of sex determination (SD), and yet how the populations maintain proper sex ratio is poorly understood. Here Tetrahymena thermophila, a ciliate with seven mating types (sexes) and probabilistic SD mechanism, is analyzed from the standpoint of population genetics. It is found based on a newly developed population genetics model that there are plenty of opportunities for both the co-existence of all seven sexes and the fixation of a single sex, pending on several factors, including the strength of natural selection. To test the validity of predictions, five experimental populations of T. thermophila were maintained in the laboratory so that the factors that can influence the dynamics of sex ratio could be controlled and measured. Furthermore, whole-genome sequencing was employed to examine the impact of newly arisen mutations. Overall, it is found that the experimental observations highly support theoretical predictions. It is expected that the newly established theoretical framework is applicable in principle to other multi-sex organisms to bring more insight into the understanding of the maintenance of multiple sexes in a natural population.

scholarly journals Is Evolution of Mating Preferences Inevitable? Random Mating in the Multisex System of Tetrahymena thermophila

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Sujal S. Phadke ◽  
Lauren Cooper ◽  
Rebecca A. Zufall
Keyword(s):  
Theoretical Model ◽  
Mate Choice ◽  
Sex Ratio ◽  
Sexual Differentiation ◽  
Mating Systems ◽  
Tetrahymena Thermophila ◽  
Random Mating ◽  
Maximum Amount ◽  
Mating Preferences ◽  
Mechanistic Basis

Ciliate mating systems are highly diversified, providing unique opportunities to study sexual differentiation and its implications for mating dynamics. Many species of ciliates have multiple (>2) sexes. More sexes may mean more choice and an opportunity for evolution of preferential mating. We asked if the multiple sexes of the ciliate Tetrahymena thermophila mate preferentially among each other. We quantified pairing frequencies among four sexes of T. thermophila using experiments that allowed the sexes to compete as mating partners. We found that all sexes mated equally frequently among each other, that is, we found no evidence of preferential mating with respect to sex. This suggests that the “mate choice” in this ciliate is binary, between whether to form a pair or not and, in this regard, sex facilitates only self-/non-self-distinction. Thus, presence of multiple sexes does not necessarily result in the evolution of mating bias, which could decrease the maximum amount of mating that would otherwise be possible in a population. Our result of random mating verifies a key assumption in the theoretical model of sex ratio evolution in T. thermophila. Investigation into molecular differences between the sexes will be necessary to reveal the mechanistic basis of random mating among them.

scholarly journals Drivers of Mating Type Composition in Tetrahymena thermophila

2020 ◽  
Vol 12 (12) ◽  
pp. 2328-2343
Author(s):  
Guangying Wang ◽  
Kai Chen ◽  
Jing Zhang ◽  
Shanjun Deng ◽  
Jie Xiong ◽  
...  
Keyword(s):  
Natural Selection ◽  
Mating Type ◽  
Tetrahymena Thermophila ◽  
Evolutionary Strategies ◽  
Whole Genome ◽  
Mating Types ◽  
Type Composition ◽  
Theoretical Predictions ◽  
Single Mating

Abstract Sex offers advantages even in primarily asexual species. Some ciliates appear to utilize such reproductive strategy with many mating types. However, the factors determining the composition of mating types in the unicellular ciliate Tetrahymena thermophila are poorly understood, and this is further complicated by non-Mendelian determination of mating type in the offspring. We therefore developed a novel population genetics model to predict how various factors influence the dynamics of mating type composition, including natural selection. The model predicted either the coexistence of all seven mating types or fixation of a single mating type in a population, depending on parameter combinations, irrespective of natural selection. To understand what factor(s) may be more influential and to test the validity of theoretical prediction, five replicate populations were maintained in laboratory such that several factors could be controlled or measured. Whole-genome sequencing was used to identify newly arising mutations and determine mating type composition. Strikingly, all populations were found to be driven by strong selection on newly arising beneficial mutations to fixation of their carrying mating types, and the trajectories of speed to fixation agreed well with our theoretical predictions. This study illustrates the evolutionary strategies that T. thermophila can utilize to optimize population fitness.

Instability and Collapse in Discrete Wave Equations

2005 ◽  
Vol 5 (3) ◽  
pp. 223-241
Author(s):  
A. Carpio ◽  
G. Duro
Keyword(s):  
Continuum Limit ◽  
Wave Equations ◽  
Numerical Solutions ◽  
Blow Up ◽  
Theoretical Predictions ◽  
Initial States ◽  
The Impact ◽  
The Continuum

AbstractUnstable growth phenomena in spatially discrete wave equations are studied. We characterize sets of initial states leading to instability and collapse and obtain analytical predictions for the blow-up time. The theoretical predictions are con- trasted with the numerical solutions computed by a variety of schemes. The behavior of the systems in the continuum limit and the impact of discreteness and friction are discussed.

scholarly journals Changing landscapes: Gay men in the west and northwest of Ireland

Sexualities ◽  
2020 ◽  
pp. 136346072098169
Author(s):  
Aidan McKearney
Keyword(s):  
Gay Men ◽  
Social Rights ◽  
Irish Society ◽  
Recent Past ◽  
Same Sex ◽  
Lgbt People ◽  
The Many ◽  
Northwest Region ◽  
The Impact ◽  
Insight Into

This article focuses on the experiences of gay men in the rural west and northwest region of Ireland, during a period of transformational social and political change in Irish society. These changes have helped facilitate new forms of LGBTQI visibility, and local radicalism in the region. Same-sex weddings, establishment of rural LGBT groups and marching under an LGBT banner at St Patricks Day parades would have been unthinkable in the recent past; but they are now becoming a reality. The men report continuing challenges in their lives as gay men in the nonmetropolitan space, but the emergence of new visibility, voice and cultural acceptance of LGBT people is helping change their lived experiences. The study demonstrates the impact of local activist LGBT citizens. Through their testimonies we can gain an insight into the many, varied and interwoven factors that have interplayed to create the conditions necessary for the men to: increasingly define themselves as gay to greater numbers of people in their localities; to embrace greater visibility and eschew strategies of silence; and aspire to a host of legal, political, cultural and social rights including same-sex marriage. Organic forms of visibility and local radicalism have emerged in the region and through an analysis of their testimonies we can see how the men continue to be transformed by an ever-changing landscape.

Double, triple or quadruple hits? Exploring the impact of cybercrime on victims in the Netherlands

2021 ◽  
pp. 026975802110106
Author(s):  
Raoul Notté ◽  
E.R. Leukfeldt ◽  
Marijke Malsch
Keyword(s):  
Public Opinion ◽  
Literature Review ◽  
The Netherlands ◽  
Public Discourse ◽  
Moral Judgments ◽  
Victim Blaming ◽  
High Prevalence ◽  
Different Types ◽  
The Impact ◽  
Insight Into

This article explores the impact of online crime victimisation. A literature review and 41 interviews – 19 with victims and 22 with experts – were carried out to gain insight into this. The interviews show that most impacts of online offences correspond to the impacts of traditional offline offences. There are also differences with offline crime victimisation. Several forms of impact seem to be specific to victims of online crime: the substantial scale and visibility of victimhood, victimisation that does not stop in time, the interwovenness of online and offline, and victim blaming. Victims suffer from double, triple or even quadruple hits; it is the accumulation of different types of impact, enforced by the limitlessness in time and space, which makes online crime victimisation so extremely invasive. Furthermore, the characteristics of online crime victimisation greatly complicate the fight against and prevention of online crime. Finally, the high prevalence of cybercrime victimisation combined with the severe impact of these crimes seems contradictory with public opinion – and associated moral judgments – on victims. Further research into the dominant public discourse on victimisation and how this affects the functioning of the police and victim support would be valuable.

scholarly journals Using syndromic measures of mortality to capture the dynamics of COVID-19 in Java, Indonesia, in the context of vaccination rollout

BMC Medicine ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Bimandra A. Djaafara ◽  
Charles Whittaker ◽  
Oliver J. Watson ◽  
Robert Verity ◽  
Nicholas F. Brazeau ◽  
...  
Keyword(s):  
Rural Areas ◽  
Vaccination Campaign ◽  
Control Measures ◽  
Additional Insight ◽  
Short Term ◽  
If Current ◽  
Vaccine Impact ◽  
Potential Impact ◽  
The Impact ◽  
Insight Into

Abstract Background As in many countries, quantifying COVID-19 spread in Indonesia remains challenging due to testing limitations. In Java, non-pharmaceutical interventions (NPIs) were implemented throughout 2020. However, as a vaccination campaign launches, cases and deaths are rising across the island. Methods We used modelling to explore the extent to which data on burials in Jakarta using strict COVID-19 protocols (C19P) provide additional insight into the transmissibility of the disease, epidemic trajectory, and the impact of NPIs. We assess how implementation of NPIs in early 2021 will shape the epidemic during the period of likely vaccine rollout. Results C19P burial data in Jakarta suggest a death toll approximately 3.3 times higher than reported. Transmission estimates using these data suggest earlier, larger, and more sustained impact of NPIs. Measures to reduce sub-national spread, particularly during Ramadan, substantially mitigated spread to more vulnerable rural areas. Given current trajectory, daily cases and deaths are likely to increase in most regions as the vaccine is rolled out. Transmission may peak in early 2021 in Jakarta if current levels of control are maintained. However, relaxation of control measures is likely to lead to a subsequent resurgence in the absence of an effective vaccination campaign. Conclusions Syndromic measures of mortality provide a more complete picture of COVID-19 severity upon which to base decision-making. The high potential impact of the vaccine in Java is attributable to reductions in transmission to date and dependent on these being maintained. Increases in control in the relatively short-term will likely yield large, synergistic increases in vaccine impact.

Insight into the impact of EGFR L792Y/F/H mutations on sensitivity to osimertinib: an in silico study

2021 ◽  
Vol 45 (10) ◽  
pp. 4756-4765
Author(s):  
Daoxing Chen ◽  
Liting Zhang ◽  
Yanan Liu ◽  
Jiali Song ◽  
Jingwen Guo ◽  
...  
Keyword(s):  
In Silico ◽  
In Silico Study ◽  
The Impact ◽  
Insight Into

EGFR L792Y/F/H mutation makes it difficult for Osimertinib to recognize ATP pockets.

The RUMA Alliance targets: an overview

Livestock ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 176-179
Author(s):  
Chris Lloyd
Keyword(s):  
Task Force ◽  
Animal Health ◽  
Antibiotic Use ◽  
Codes Of Practice ◽  
The Government ◽  
The Uk ◽  
Ongoing Support ◽  
The Impact ◽  
Insight Into ◽  
Roll Out

The Responsible Use of Medicines in Agriculture Alliance (RUMA) was established to promote the highest standards of food safety, animal health and animal welfare in the British livestock industry. It has a current focus to deliver on the Government objective of identifying sector-specific targets for the reduction, refinement or replacement of antibiotics in animal agriculture. The creation and roll out of sector specific targets in 2017 through the RUMA Targets Task Force, has helped focus activity across the UK livestock sectors to achieve a 50% reduction in antibiotic use since 2014. This has been realised principally through voluntary multi-sector collaboration, cross sector initiatives, codes of practice, industry body support and farm assurance schemes. This article provides an overview of RUMA's work to date providing insight into the methods used to create the targets, why they are so important, the impact they are having and how ongoing support and robust data are vital components in achieving the latest set of targets.

scholarly journals The Impact of Spaceflight and Microgravity on the Human Islet-1+ Cardiovascular Progenitor Cell Transcriptome

2021 ◽  
Vol 22 (7) ◽  
pp. 3577
Author(s):  
Victor Camberos ◽  
Jonathan Baio ◽  
Ana Mandujano ◽  
Aida F. Martinez ◽  
Leonard Bailey ◽  
...  
Keyword(s):  
Early Stage ◽  
Space Station ◽  
Cardiovascular Development ◽  
Support Cell ◽  
Cell Transcriptome ◽  
Islet 1 ◽  
Life On Earth ◽  
The Impact ◽  
And Oxidative Stress ◽  
Insight Into

Understanding the transcriptomic impact of microgravity and the spaceflight environment is relevant for future missions in space and microgravity-based applications designed to benefit life on Earth. Here, we investigated the transcriptome of adult and neonatal cardiovascular progenitors following culture aboard the International Space Station for 30 days and compared it to the transcriptome of clonally identical cells cultured on Earth. Cardiovascular progenitors acquire a gene expression profile representative of an early-stage, dedifferentiated, stem-like state, regardless of age. Signaling pathways that support cell proliferation and survival were induced by spaceflight along with transcripts related to cell cycle re-entry, cardiovascular development, and oxidative stress. These findings contribute new insight into the multifaceted influence of reduced gravitational environments.

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