Pinpointing the 'silent' mutations that gave the coronavirus an evolutionary edge

RNA folding may help explain how the coronavirus became so hard to stop after it spilled over from wildlife to humans.

DUKE UNIVERSITY

Research News

 

DURHAM, N.C. -- We know that the coronavirus behind the COVID-19 crisis lived harmlessly in bats and other wildlife before it jumped the species barrier and spilled over to humans.

Now, researchers at Duke University have identified a number of "silent" mutations in the roughly 30,000 letters of the virus's genetic code that helped it thrive once it made the leap -- and possibly helped set the stage for the global pandemic. The subtle changes involved how the virus folded its RNA molecules within human cells.

For the study, published Oct. 16 in the journal PeerJ, the researchers used statistical methods they developed to identify adaptive changes that arose in the SARS-CoV-2 genome in humans, but not in closely related coronaviruses found in bats and pangolins.

"We're trying to figure out what made this virus so unique," said lead author Alejandro Berrio, a postdoctoral associate in biologist Greg Wray's lab at Duke.

Previous research detected fingerprints of positive selection within a gene that encodes the "spike" proteins studding the coronavirus's surface, which play a key role in its ability to infect new cells.

The new study likewise flagged mutations that altered the spike proteins, suggesting that viral strains carrying these mutations were more likely to thrive. But with their approach, study authors Berrio, Wray and Duke Ph.D. student Valerie Gartner also identified additional culprits that previous studies failed to detect.

The researchers report that so-called silent mutations in two other regions of the SARS-CoV-2 genome, dubbed Nsp4 and Nsp16, appear to have given the virus a biological edge over previous strains without altering the proteins they encode.

Instead of affecting proteins, Berrio said, the changes likely affected how the virus's genetic material -- which is made of RNA -- folds up into 3-D shapes and functions inside human cells.

What these changes in RNA structure might have done to set the SARS-CoV-2 virus in humans apart from other coronaviruses is still unknown, Berrio said. But they may have contributed to the virus's ability to spread before people even know they have it -- a crucial difference that made the current situation so much more difficult to control than the SARS coronavirus outbreak of 2003.

The research could lead to new molecular targets for treating or preventing COVID-19, Berrio said.

"Nsp4 and Nsp16 are among the first RNA molecules that are produced when the virus infects a new person," Berrio said. "The spike protein doesn't get expressed until later. So they could make a better therapeutic target because they appear earlier in the viral life cycle."

More generally, by pinpointing the genetic changes that enabled the new coronavirus to thrive in human hosts, scientists hope to better predict future zoonotic disease outbreaks before they happen.

"Viruses are constantly mutating and evolving," Berrio said. "So it's possible that a new strain of coronavirus capable of infecting other animals may come along that also has the potential to spread to people, like SARS-CoV-2 did. We'll need to be able to recognize it and make efforts to contain it early."

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CITATION: "Positive Selection Within the Genomes of SARS-CoV-2 and Other Coronaviruses Independent of Impact on Protein Function," Alejandro Berrio, Valerie Gartner, Gregory A Wray. PeerJ, October 16, 2020. DOI: 10.7717/peerj.10234

Stopping the virus and closing borders

Countries with international travel restrictions suffered fewer COVID-19 fatalities

WZB BERLIN SOCIAL SCIENCE CENTER

Research News

 

Until mid-March 2020, the WHO, the EU as well as German authorities were convinced that the spread of the virus could not be curbed by border closures. "This belief was fatally mistaken", argues Ruud Koopmans. "Travel restrictions should be given much greater weight", he urges. "This holds true for containing upcoming waves of the COVID-19 pandemic as well as similar pandemics in the future."

The study draws on sociological accounts of network diffusion and shows that countries that are heavily exposed to international travel and tourism - such as France, Italy, and the USA - recorded significantly higher numbers of deaths. At the same time, death rates in countries more at the margins of international travel networks as well in island states remained comparatively low.

In view of this key role of international travel flows, the study examines the effects of entry bans and mandatory quarantines on COVID-19 mortality. The earlier such travel restriction measures were implemented, the greater was their limiting effect on mortality. Crucially, travel restrictions needed to be in place before the local spread of the virus had spiraled out of control. If one compares countries that imposed travel restrictions until early March to countries that implement them from mid-March onward or not at all, mortality within the first group is an estimated62 percentage points lower than in the second group.

Among the early adopters of travel restrictions with significantly lower death rates are countries such as Australia, Israel and the Czech Republic. Germany, which introduced its first travel restrictions on 16 March, belongs to the late-adopter group, but countries such as Great Britain, France or Brazil responded even later.

The study shows that the type of travel restriction also plays a role. Mandatory quarantines for incoming travelers were more effective than entry bans. A plausible explanation is that entry bans often include exceptions for both citizens and permanent residents. By contrast, quarantine measures tend to apply to all incoming travelers, regardless of their nationality or country of residence. The study further shows that targeted travel restrictions (represented in the study by entry bans and mandatory quarantines for travelers from China or Italy) were more effective than restrictions targeted against all foreign countries.

The study has been published as a WZB Discussion Paper:

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Ruud Koopmans: A Virus That Knows No Borders? Exposure to and Restrictions of International Travel and the Global Diffusion of COVID-19, WZB Discussion Paper SP VI 2020-103, October 2020. https://bibliothek.wzb.eu/pdf/2020/vi20-103.pdf

Ruud Koopmans is the Director of the Migration, Integration, Transnationalization Research Unit at WZB and a Professor of Sociology and Migration Research at the Humboldt-University of Berlin.

 

Covid-19: Pooled testing among recommendations to fix test, trace and isolate system

SAGE

Research News

 

In a series of recommendations to fix the struggling Covid-19 test, trace and isolate system in England, health researchers from University College London and the London School of Hygiene & Tropical Medicine say that pooled testing for Covid-19 could significantly increase testing capacity in a relatively short space of time and help with the identification of asymptomatic cases in key workers.

Writing in the Journal of the Royal Society of Medicine, the researchers say that evaluating samples in batches rather than individually, and re-testing only the groups that come up positive means fewer tests overall would be needed. Several countries, including China, USA, Germany, Portugal, New Zealand, Rwanda, Uruguay, Israel and Vietnam have used pooled testing to considerably increase testing capacity and decrease pressure on lab reagents and operators.

As positivity rates rise, however, pooling becomes less efficient because more samples have to be tested. Co-author Alex Crozier, from the Division of Biosciences at University College London, said: "We are close to missing that window of opportunity in England unless we can control transmission quickly. For now, pooling may be best reserved for surveillance testing and asymptomatic screening of healthcare workers, care homes and hospital pre-admissions."

As well as increased investment in NHS and Public Health England labs to scale up additional testing locally and making use of unused lab capacity in universities and research institutes where possible, the recommendations include the initiation of environmental surveillance by testing wastewater as an early warning system for Covid-19 outbreaks.

The authors also recommend a major investment in people on the ground to support contact tracing. Pointing to Massachusetts where a $44 million contact tracing programme hired and trained 1,000 people to support existing local public health volunteers, the researchers write that this approach is much less costly than the UK government's £100 billion 'Operation Moonshot', and has reached 91.8% of cases and 78.8% of contacts. Recognising the important role played by superspreading events, another of the recommendations is to increase resources to enable a greater focus on identifying clusters using retrospective tracing, as seen in several countries that have been most successful such as Japan, South Korea, and Uruguay.

Another of the authors, Professor Martin Mckee, of the London School of Hygiene & Tropical Medicine, said: "England stands on the edge of a precipice: find, test, trace, isolate and support strategies need to be re-thought to have any chance of avoiding a considerable rise in cases over the coming months requiring a return to stricter social distancing measures nationwide. Our recommendations are feasible, do not require further individual sacrifice and would likely have a significant impact on driving down the reproductive number and reducing the socio-economic impact of the pandemic if they were implemented quickly."

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Malice leaves a nasty smell

Bad attitudes lead to moral judgments rooted in our basic survival mechanisms. And scientists from UNIGE have demonstrated that they are linked to foul smells.

UNIVERSITÉ DE GENÈVE

Research News

 

IMAGE: PART OF THE HUMAN BRAIN CONTRIBUTING THE MOST TO THE PREDICTION OF PAIN AND OLFACTORY DISGUST. view more 

CREDIT: UNIGE/CORRADI-DELL'AQUA

Unhealthy behaviours trigger moral judgments that are similar to the basic emotions that contribute to our ability to survive. Two different hypotheses are to be found in the current scientific literature as to the identity of these emotions. Some researchers single out disgust, while others opt for pain. After developing a new approach to brain imaging, a research team from the University of Geneva (UNIGE) has come down on the side of disgust. The study, which can be found in Science Advances, shows that unhealthy behaviours trigger brain responses that are similar to those prompted by bad smells. The research also identifies for the first time a biomarker in the brain for disgust.

Disgust is a basic emotion linked to our survivability. Smell provides information about the freshness of foodstuffs, while disgust means we can take action to avoid a potential source of poisoning. Following the same principle, pain helps us cope with any injuries we might suffer by activating our withdrawal reflexes. Psychologists believe that these types of survival reflexes might come into play in response to other people's bad behaviour.

Disgust or pain

"These connections have been demonstrated via associations between situations and sensations," begins Professor Corrado Corradi-Dell'Acqua, a researcher in UNIGE's Department of Psychology and the study's lead investigator. "For instance, if I drink something while reading an article about corruption that affects my moral judgment, I may find that my drink smells bad and tastes vile. Equally, the reverse is true: smells can generate inappropriate moral judgment. In concrete terms, if someone smells bad, other people tend to make the judgment that they're unhealthy."

While some studies suggest that disgust is involved in the process, others opt for pain, since they consider that moral judgments are made based on actual facts - hence the parallel with the mechanisms involved in pain. "If a driver is distracted, and does not see a pedestrian crossing a road, I will judge this person more negatively if the pedestrian was actually harmed, rather than avoided by chance", explains the psychologist. His team set up an experimental paradigm and customised magnetic resonance imaging (MRI) techniques in an attempt to decide between the contradictory hypotheses.

The train dilemma as a paradigm

The first step was for Corradi-Dell'Acqua's laboratory to subject volunteers to unpleasant odours or heat-induced pain. "The whole idea was to elicit a similar degree of discomfort with the two techniques so that they could work on the same levels." Once the calibration had been performed, participants in the study were subjected to readings that evoked value judgments. "We used the train dilemma when five people are stuck on a railway track as a train approaches. The only possible way to save them is to push someone off the top of a bridge so that the switch is hit as they fall. In other words, it's necessary to kill one person to save five in a highly immoral situation," explains the researcher. The act of reading this unpleasant dilemma had an influence on the odours the participants smelt and caused disgust, but did not influence the pain, an outcome that was backed up by the participants' electrodermal activity. This is a physiological measurement of the electrical conductance of the skin. It reflects the rate of sweating and the activity of the nervous system responsible for involuntary behaviour.

Neural pathways identified

Professor Corradi-Dell'Acqua then concentrated on the brain response. "It is difficult to infer pain and disgust from neural activity, as these two experiences often recruit the same brain areas. To dissociate them, we had to measure the global neuronal activity via MRI rather than focusing on specific regions," summarises the researcher. The Geneva team adopted a technique that allows predicting disgust and pain from the overall brain activity, such as specific biomarkers.

Using this tool, the researchers were able to prove that the overall brain response to disgust was influenced by previous moral judgment. Once again, moral judgments are indeed associated with disgust. "In addition to this important discovery for psychology, this study was the occasion for the development of a biomarker prototype for olfactory disgust. It's a double step forward!" concludes Corradi-Dell'Acqua.

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DEMONOLOGY

Researchers discover a uniquely quantum effect in erasing information

TRINITY COLLEGE DUBLIN

Research News

 

IMAGE: A BIT OF INFORMATION CAN BE ENCODED IN THE POSITION OF A PARTICLE (LEFT OR RIGHT). A DEMON CAN ERASE A CLASSICAL BIT (BLUE) BY RAISING ONE SIDE UNTIL THE... view more 

CREDIT: PROFESSOR GOOLD, TRINITY COLLEGE DUBLIN

Researchers from Trinity College Dublin have discovered a uniquely quantum effect in erasing information that may have significant implications for the design of quantum computing chips. Their surprising discovery brings back to life the paradoxical "Maxwell's demon", which has tormented physicists for over 150 years.

The thermodynamics of computation was brought to the fore in 1961 when Rolf Landauer, then at IBM, discovered a relationship between the dissipation of heat and logically irreversible operations. Landauer is known for the mantra "Information is Physical", which reminds us that information is not abstract and is encoded on physical hardware.

The "bit" is the currency of information (it can be either 0 or 1) and Landauer discovered that when a bit is erased there is a minimum amount of heat released. This is known as Landauer's bound and is the definitive link between information theory and thermodynamics.

Professor John Goold's QuSys group at Trinity is analysing this topic with quantum computing in mind, where a quantum bit (a qubit, which can be 0 and 1 at the same time) is erased.

In just-published work in the journal, Physical Review Letters, the group discovered that the quantum nature of the information to be erased can lead to large deviations in the heat dissipation, which is not present in conventional bit erasure.

Thermodynamics and Maxwell's demon

One hundred years previous to Landauer's discovery people like Viennese scientist, Ludwig Boltzmann, and Scottish physicist, James Clerk Maxwell, were formulating the kinetic theory of gases, reviving an old idea of the ancient Greeks by thinking about matter being made of atoms and deriving macroscopic thermodynamics from microscopic dynamics.

Professor Goold says:

"Statistical mechanics tells us that things like pressure and temperature, and even the laws of thermodynamics themselves, can be understood by the average behavior of the atomic constituents of matter. The second law of thermodynamics concerns something called entropy which, in a nutshell, is a measure of the disorder in a process. The second law tells us that in the absence of external intervention, all processes in the universe tend, on average, to increase their entropy and reach a state known as thermal equilibrium.

"It tells us that, when mixed, two gases at different temperatures will reach a new state of equilibrium at the average temperature of the two. It is the ultimate law in the sense that every dynamical system is subject to it. There is no escape: all things will reach equilibrium, even you!"

However, the founding fathers of statistical mechanics were trying to pick holes in the second law right from the beginning of the kinetic theory. Consider again the example of a gas in equilibrium: Maxwell imagined a hypothetical "neat-fingered" being with the ability to track and sort particles in a gas based on their speed.

Maxwell's demon, as the being became known, could quickly open and shut a trap door in a box containing a gas, and let hot particles through to one side of the box but restrict cold ones to the other. This scenario seems to contradict the second law of thermodynamics as the overall entropy appears to decrease and perhaps physics' most famous paradox was born.

But what about Landauer's discovery about the heat-dissipated cost of erasing information? Well, it took another 20 years until that was fully appreciated, the paradox solved, and Maxwell's demon finally exorcised.

Landauer's work inspired Charlie Bennett - also at IBM - to investigate the idea of reversible computing. In 1982 Bennett argued that the demon must have a memory, and that it is not the measurement but the erasure of the information in the demon's memory which is the act that restores the second law in the paradox. And, as a result, computation thermodynamics was born.

New findings

Now, 40 years on, this is where the new work led by Professor Goold's group comes to the fore, with the spotlight on quantum computation thermodynamics.

In the recent paper, published with collaborator Harry Miller at the University of Manchester and two postdoctoral fellows in the QuSys Group at Trinity, Mark Mitchison and Giacomo Guarnieri, the team studied very carefully an experimentally realistic erasure process that allows for quantum superposition (the qubit can be in state 0 and 1 at same time).

Professor Goold explains:

"In reality, computers function well away from Landauer's bound for heat dissipation because they are not perfect systems. However, it is still important to think about the bound because as the miniaturisation of computing components continues, that bound becomes ever closer, and it is becoming more relevant for quantum computing machines. What is amazing is that with technology these days you can really study erasure approaching that limit.

"We asked: 'what difference does this distinctly quantum feature make for the erasure protocol?' And the answer was something we did not expect. We found that even in an ideal erasure protocol - due to quantum superposition - you get very rare events which dissipate heat far greater than the Landauer limit.

"In the paper we prove mathematically that these events exist and are a uniquely quantum feature. This is a highly unusual finding that could be really important for heat management on future quantum chips - although there is much more work to be done, in particular in analysing faster operations and the thermodynamics of other gate implementations.

"Even in 2020, Maxwell's demon continues to pose fundamental questions about the laws of nature."

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The journal article is available at: https://bit.ly/2FwH8aF

 

The mental health impact of pandemics for front line health care staff

UNIVERSITY OF EAST ANGLIA

Research News

 

Mental health problems such as Post-Traumatic Stress Disorder, anxiety and depression are common among healthcare staff during and immediately after pandemics - according to new research from the University of East Anglia.

Researchers investigated how treating patients in past pandemics such as SARS and MERS affected the mental health of front-line staff.

They found that almost a quarter of health-care workers (23.4 per cent) experienced PTSD symptoms during the most intense 'acute' phase of previous pandemic outbreaks - with 11.9 per cent of carers still experiencing symptoms a year on.

They also looked at data about elevated levels of mental distress and found that more than a third of health workers (34.1 per cent) experienced symptoms such as anxiety or depression during the acute phase, dropping to 17.9 per cent after six months. This figure however increased again to 29.3 per cent after 12 months or longer.

The team hope that their work will help highlight the impact that the Covid-19 pandemic could be having on the mental health of doctors and nurses around the world.

Prof Richard Meiser-Stedman, from UEA's Norwich Medical School, said: "We know that Covid-19 poses unprecedented challenges to the NHS and to healthcare staff worldwide.

"Nurses, doctors, allied health professionals and all support staff based in hospitals where patients with Covid-19 are treated are facing considerable pressure, over a sustained period.

"In addition to the challenge of treating a large volume of severely unwell patients, front line staff also have to contend with threats to their own physical health through infection, particularly as they have had to face shortages of essential personal protective equipment.

"The media has reported that healthcare workers treating coronavirus patients will face a 'tsunami' of mental health problems as a result of their work.

"We wanted to examine this by looking closely at the existing data from previous pandemics to better understand the potential impact of Covid-19.

"We estimated the prevalence of common mental health disorders in health care workers based in pandemic-affected hospitals. And we hope our work will help inform hospital managers of the level of resources required to support staff through these difficult times."

A team of trainee clinical psychologists - Sophie Allan, Rebecca Bealey, Jennifer Birch, Toby Cushing, Sheryl Parke and Georgina Sergi - all from UEA's Norwich Medical School, investigated how previous pandemics affected healthcare workers' mental health, with support from Prof Meiser-Stedman and Dr Michael Bloomfield, University College London.

They looked at 19 studies which included data predominantly from the SARS outbreak in Asia and Canada, and which tended to focus on the acute stage of the pandemic - during and up to around six weeks after the pandemic.

Sophie Allan said: "We found that post-traumatic stress symptoms were elevated during the acute phase of a pandemic and at 12 months post-pandemic.

"There is some evidence that some mental health symptoms such as Post Traumatic Stress symptoms get better naturally over time but we cannot be sure about this. The studies we looked at had very different methods - for example they used different questionnaires about mental health - so we need to be cautious about the results.

"We didn't find any differences between doctors and nurses experiencing PTSD or other psychiatric conditions, but the available data was limited and more research is needed to explore this.

"Overall there are not enough studies examining the impact of pandemics on the mental health of healthcare staff. More research is needed that focusses on Covid-19 specifically and looks at the mental health of healthcare workers longer-term," she added.

'The prevalence of common and stress-related mental health disorders in healthcare workers based in pandemic-affected hospitals: a rapid systematic review and meta-analysis' is published in the European Journal of Psychotraumatology on October 16, 2020.

 

Humans and climate drove giants of Madagascar to extinction

UNIVERSITY OF INNSBRUCK

Research News

 

IMAGE: INVESTIGATING THE DRIVERS OF EXTINCTION: BY ANALYZING STALAGMITES FROM THE LA VIERGE CAVE LOCATED ON RODRIGUES THE SCIENTISTS RECONSTRUCTED 8000 YEARS OF THE REGION'S PAST CLIMATE. view more 

CREDIT: HANYING LI

Nearly all of Madagascan megafauna - including the famous Dodo bird, gorilla-sized lemurs, giant tortoises, and the Elephant Bird which stood 3 meters tall and weighted close to a half ton - vanished between 1500 and 500 years ago. Were these animals overhunted to extinction by humans? Or did they disappear because of climate change? There are numerous hypotheses, but the exact cause of this megafauna crash remains elusive and hotly debated. The Mascarene islands east of Madagascar are of special interest because they are among the last islands on earth to be colonized by humans. Intriguingly, the islands' megafauna crashed in just a couple of centuries following human settlement. In a recent study published by Science Advances, a team of international researchers found that it was likely a "double whammy" of heightened human activities in combination with a particularly severe spell of region-wide aridity that may have doomed the megafauna. The researchers rule out climate change as the one and only cause, and instead suggest that the impact of human colonization was a crucial contributor to the megafaunal collapse. Hanying Li, a postdoctoral scholar at the Xi'an Jiaotong University in China and the lead author of this study, pieced together a detailed history of the regional climate variations. The primary source of this new paleoclimate record came from the tiny Mascarene island of Rodrigues in the southwest Indian Ocean approximately 1600 km east of Madagascar. "An island so remote and small that one will not find it on most schoolbook atlases," says Gayatri Kathayat, one of the co-authors and an associate professor of climate science at Xi'an Jiaotong University.

Analysis of Cave Deposits

Li and colleagues built their climate records by analyzing the trace elements and carbon and oxygen isotopes from each incremental growth layer of stalagmites which they collected from one of the many caves from this island. The bulk of these analyses were conducted at the Quaternary Research Group at the Institute of Geology at the University of Innsbruck, led by Prof. Christoph Spötl: "Variations in the geochemical signatures provided the information needed to reconstruct the region's rainfall patterns over the last 8000 years. To analyze the stalagmites we used the stable isotope method in our lab in Innsbruck". Despite the distance between the two islands, the summer rainfall at Rodrigues and Madagascar is influenced by the same global-wide tropical rain belt that oscillates north and south with the seasons." And when this belt falters and stays further north of Rodrigues, droughts can strike the whole region from Madagascar to Rodrigues," Hai Cheng explains, the study's senior coauthor. "Li's work from Rodrigues demonstrates that the hydroclimate of the region experienced a series of drying trends throughout the last 8 millennia, which were frequently punctuated by 'megadroughts' that lasted for decades," notes Hubert Vonhof, scientist at Max Planck Institute of Chemistry in Mainz, Germany and coauthor.

Resilient to climate stress

The most recent of the drying trends in the region commenced around 1500 years ago at a time when the archaeological and proxy records began to show definitive signs of increased human presence on the island. "While we cannot say with 100 percent certainty whether human activity, such as overhunting or habitat destruction, was the proverbial last straw that broke the camel's back, our paleoclimate records make a strong case that the megafauna had survived through all the previous episodes of even greater aridity. This resilience to past climate swings suggests that an additional stressor contributed to the elimination of the region's megafauna," notes Ashish Sinha, professor of earth science at California State University Dominguez Hills, USA. "There are still many pieces missing to fully solve the riddle of megafauna collapse. This study now provides an important multi-millennial climatic context to megafaunal extinction," says Ny Rivao Voarintsoa from KU Leuven in Belgium, a native of Madagascar, who participated in this research. The study sheds new light on the decimation of flora and fauna of Mauritius and Rodrigues: "Both islands were rapidly stripped of endemic species of vertebrates within two centuries of the initial human colonization, including the well-known flightless 'Dodo' bird from Mauritius and the saddle-backed 'Rodrigues giant tortoise' endemic to Rodrigues," adds Aurele Anquetil André, the reserve manager and chief conservator at the Francois Leguat Giant Tortoise and Cave Reserve at Rodrigues.

"The story our data tells is one of resilience and adaptability of the islands' ecosystems and fauna in enduring past episodes of severe climate swings for eons - until they were hit by human activities and climate change", the researchers conclude.

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Publication:

H. Li, A. Sinha, A. Anquetil André, C. Spötl, H. B. Vonhof, A. Meunier, G. Kathayat, P. Duan, N. R. G. Voarintsoa, Y. Ning, J. Biswas, P. Hu, X. Li, L. Sha, J. Zhao, R. L. Edwards, H. Cheng, A multimillennial climatic context for the megafaunal extinctions in Madagascar and Mascarene Islands. Sci. Adv. 6, eabb2459 (2020).

DOI: 10.1126/sciadv.abb2459

 

Explaining teamwork in male lions

UNIVERSITY OF MINNESOTA

Research News

 

Animal cooperation typically involves sharing crucial resources -- and the rules of sharing get complicated, especially when males are involved.

Natural selection theory dictates that males generally compete with each other for food and mates. Thus male cooperation in the animal world is an enigma, especially among unrelated animals.

In a new paper published in Scientific Reports, biologists from the Wildlife Institute of India and the University of Minnesota demonstrated the hows and whys of cooperation among male lions. By studying one of the rarest lion populations in the world -- the Asian lions that live as a single population in the Gir Forest of India -- researchers found that cooperation among lions does not necessarily indicate that they are related.

"In a 2017 study, we detailed the behavioural nuances of why male lions cooperate: to better protect their territories and have more access to mating opportunities than males who live alone," said study lead author Stotra Chakrabarti, a postdoctoral research associate in the Department of Fisheries, Wildlife, and Conservation Biology at the University of Minnesota. "However, a lack of genetic data from the population at this stage had prevented us from determining if such cooperation extended to relatives only, or whether non-kin were included as well."

Subsequent monitoring of individual lions and collection of tissue, hair and blood samples from known individuals set the stage to find out whether the cooperating males were related or they came together by chance.

"Genetic analyses of the Gir lions were tricky because they have undergone two population bottlenecks that have rendered discerning kin versus non-kin quite challenging," said Vishnupriya Kolipakam, co-author and faculty at the Wildlife Institute of India..

By synthesizing long-term behavioural and genetic records of known mothers, offspring and siblings, researchers were able to develop a baseline panel against which male coalition partners were compared to understand the level of relatedness between them.

By observing 23 male lions belonging to 10 coalitions, Chakrabarti and co-authors could identify that males who lived in large coalitions (such as trios and quartets) were typically brothers and cousins, but more than 70 percent of pairs consisted of unrelated males.

In large coalitions, sharing is costlier because resources are divided between many lions, and often low-ranking partners are excluded from opportunities to breed. Such coalitions are only possible between related animals.

"Forgoing mating opportunities is generally a severe evolutionary cost, unless in doing so you help related individuals," said Joseph Bump, co-author and associate professor at the University of Minnesota. "As a consequence, this evidence supports a conclusion that large male lion coalitions are feasible only when all partners are brothers and/or cousins."

Large coalitions fared the best as a group, but the fitness of individual lions -- measured by the number of potential offspring sired -- was higher in pairs. Such high fitness for individual male lions in pairs allowed even unrelated individuals to team up, because pairs always fared better than single males in terms of territory and mate acquisition.

"The results of our study show that male coalitions prosper better than loners in established lion societies and this can have crucial implications for their conservation, especially when establishing new populations through reintroductions," said YV Jhala, principal investigator of the Gir lion project and the Dean of the Wildlife Institute of India.

Though large coalitions fared better as a group, they are rare in the Gir system because so few sets of sibling lions grow to maturity. An analysis of 20 years of lion demography data indicates only 12%-13% of the observed lion coalitions in Gir are made of three or four males.

"This calculation of demography and the availability of kin to support cooperation is often missing from studies on animal societies, but it is of fundamental value that enhances our understanding of how optimality in group formation is constrained in the real world," Jhala said.

The study revealed new details about the behavior of male lions. For example, in a rare observation, researchers determined one of the study's coalitions could be a father-son duo because they were related and had an age difference of about five years.

"Such an observation was only possible because we could combine field observations with genetic data, and it shows that there could be multiple pathways for coalition formation in lions," said Kolipakam.

Researchers also observed that related male partners were no more likely to support each other during fights with rivals than unrelated partners.

"This shows that kin support is not the only reason why males cooperate with each other, but kin support makes the cooperation even more beneficial," Bump said.

The study indicates that underlying mechanisms facilitating cooperation in lions can be multifaceted.

"We have quantified the ultimate reasons why unrelated males team up, but it would be worthwhile to investigate other aspects of male cooperation, including how their bonds are forged in the first place, how they find compatible partners, what breaks the ice between them when they first meet and how they decide who will lead and who will follow." Chakrabarti said.

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COVID: women are less likely to put themselves in danger

Women's attitudes and behaviors may have contributed to their reduced vulnerability and mortality. A survey in 8 countries shows they consider Coronavirus a more serious problem than men and are more likely to approve and comply with health policies

BOCCONI UNIVERSITY

Research News

 

IMAGE: PAOLA PROFETA view more 

CREDIT: PAOLO TONATO

The increased adherence of women to Coronavirus policies may be one of the reasons for the lower vulnerability and mortality that they experienced, compared to men, in the early phase of the epidemic. "Policy makers who promote a new normality made of reduced mobility, face masks and other behavioral changes," says Vincenzo Galasso, one of the authors of a new study on gender differences in the reaction to COVID-19, "should, therefore, design a gender-differentiated communication if they want to increase the compliance of men."

Two of the authors of the research, which appeared on PNAS (Proceedings of the National Academy of Sciences) are scholars of Bocconi University, Vincenzo Galasso and Paola Profeta, affiliated to Bocconi's COVID Crisis Lab.

The authors observe substantial gender differences in both attitudes and behaviors through a two-wave survey (March and April 2020), with 21,649 respondents in Australia, Austria, France, Germany, Italy, New Zealand, the UK and the US, which is part of the international project REPEAT (REpresentations, PErceptions and ATtitudes on the COVID-19).

Women around the world are more inclined than men to consider COVID-19 a very serious health problem (59% against 48.7% in March and 39.6% against 33% in April), they are more inclined to agree with public policies that fight the pandemic, such as mobility restrictions and social distancing (54,1 against 47,7 in an index that goes from 1 to 100 in March and 42,6 against 37,4 in April) and are clearly more inclined to follow the rules concerning COVID-19 (88,1% against 83,2% in March and 77,6% against 71,8% in April).

The share of individuals complying with the rules drops over time, particularly in Germany, from 85.8% of women and 81.5% of men in March to 70.5% of women and 63.7% of men in April, but the large gender gap persists.

"The biggest differences between men and women relate to behaviors that serve to protect others above all, such as coughing in the elbow, unlike those that can protect both themselves and others," says Profeta. Gender differences persist even after the study controlled a large number of sociodemographic characteristics and psychological factors.

However, such differences are smaller among married couples, who live together and share their views with each other, and among individuals most directly exposed to the pandemic. They decrease over time if men and women are exposed to the same flow of information about the pandemic.

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Non-obese Vietnamese Americans are 60% more likely to have diabetes

Study compares non-obese Vietnamese Americans with non-obese, non-Hispanic White Americans

UNIVERSITY OF TORONTO

Research News

 

A new study has found that Vietnamese-American adults who were not obese were 60% more likely to have diabetes than non-obese, non-Hispanic, White Americans, after accounting for age, sex, sociodemographic factors, smoking history and exercise level.

Overall, only 9% of Vietnamese Americans with diabetes in the study were obese -- defined as having a body mass index (BMI) of 30 or higher. In comparison, half of all non-Hispanic White Americans with diabetes were obese.

"While obesity is commonly associated with diabetes risk, the study's findings indicate that this is not necessarily the case for Vietnamese Americans," says the study's first author Leanne R. De Souza, Assistant Professor, Human Biology and Health Studies Programs, University College, University of Toronto. "As a result, health care professionals may miss screening for preventing and treating this potentially life-threatening disease in the Vietnamese-American population. Screening of Vietnamese adults who have normal weight would be helpful."

The data set used in this study did not provide information on why non-obese Vietnamese Americans have higher odds of diabetes than White Americans, but previous research provides potential answers.

Other studies have found that accumulation of excess fat in the abdomen is higher among Asian Americans than White Americans of a similar weight.

"A growing body of literature suggests that measurement of excess weight around the liver and in the abdomen may be a better way to assess diabetes risk than merely taking into account weight and height," says co-author Keith Tsz-Kit Chan, Assistant Professor, Silberman School of Social Work at Hunter College, City University of New York.

Past research has also shown that Asian Americans are less likely to be screened and are therefore more likely to be living with undiagnosed diabetes and pre-diabetes. Untreated diabetes can result in many serious complications including nerve damage, preventable amputation, blindness, heart attacks, strokes, chronic kidney disease and kidney failure.

The authors of the present study found that among non-obese Vietnamese Americans, those aged 45 and older had at least 40-fold the odds of diabetes compared to young adults.

"These findings suggest that screening for diabetes in Vietnamese Americans starting at age 45 might be warranted," says co-author Alexis Karasiuk, a research assistant at the University of Toronto.

In the subsample of non-obese Vietnamese Americans, men and those living in poverty had a much higher prevalence of diabetes compared to women and those with higher incomes, respectively. Adults who had never smoked and those with a post-secondary degree were less likely to have diabetes.

The authors hope to examine the role of diet in future studies.

"Previous research has found that each additional portion of white rice consumed daily raises the risk of diabetes by 11%. Substituting other whole grains such as brown rice instead of white rice may be a promising strategy for decreasing this risk," noted co-author Karen Kobayashi, professor in the department of Sociology and a research fellow at the Institute on Aging & Lifelong Health at the University of Victoria.

Given that non-obese Vietnamese Americans, including those as young as 45, have a relatively high prevalence of diabetes, the authors say that routine screening of this population is needed.

"Better identification of those in the 'pre-diabetes' stage may increase awareness of personal risk and interventions to promote lifestyle changes. Such interventions may substantially decrease the risk of progression to full diabetes," says senior author, Esme Fuller-Thomson, Director of the Institute for Life Course & Aging and professor at the University of Toronto's Factor-Inwentash Faculty of Social Work and Department of Family & Community Medicine.

The author's study was based upon a representative sample of community-dwelling Californians aged 18 and older from seven combined waves of the California Health Interview Survey (CHIS) conducted between 2007 and 2016. The study sample was restricted to Vietnamese Americans (n = 3,969) and non-Hispanic whites (n = 119,651) who were non-obese, defined as having a body mass index (BMI) of less than 30.

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The study was published online ahead of press in the journal Chronic Illness.

Source Article:

De Souza LR, Chan, KT, Kobayashi, K, Karasiuk, A, Fuller-Thomson, E (2020). The prevalence and management of diabetes among Vietnamese Americans: A population-based survey of an understudied ethnic group

For interviews please contact first author, Leanne De Souza leanne.desouza@utoronto.ca or 647-787-3507, or senior author, Esme Fuller-Thomson, esme.fuller.thomson@utoronto.ca or 416 209-3231

A copy of the paper is available to credentialed journalist upon request.