SARS-CoV-2 jumped from bats to humans without much change
2021-03-12
(Press-News.org) How much did SARS-CoV-2 need to change in order to adapt to its new human host? In a research article published in the open access journal PLOS Biology Oscar MacLean, Spyros Lytras at the University of Glasgow, and colleagues, show that since December 2019 and for the first 11 months of the SARS-CoV-2 pandemic there has been very little 'important' genetic change observed in the hundreds of thousands of sequenced virus genomes.
The study is a collaboration between researchers in the UK, US and Belgium. The lead authors Prof David L Robertson (at the MRC-University of Glasgow Centre for Virus Research, Scotland) and Prof Sergei Pond (at the Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia) were able to turn their experience of analysing data from HIV and other viruses to SARS-CoV-2. Pond's state-of-the-art analytical framework, HyPhy, was instrumental in teasing out the signatures of evolution embedded in the virus genomes and rests on decades of theoretical knowledge on molecular evolutionary processes.
First author Dr Oscar MacLean explains, "This does not mean no changes have occurred, mutations of no evolutionary significance accumulate and 'surf' along the millions of transmission events, like they do in all viruses." Some changes can have an effect; for example, the Spike replacement D614G which has been found to enhance transmissibility and certain other tweaks of virus biology scattered over its genome. On the whole, though, 'neutral' evolutionary processes have dominated. MacLean adds, "This stasis can be attributed to the highly susceptible nature of the human population to this new pathogen, with limited pressure from population immunity, and lack of containment, leading to exponential growth making almost every virus a winner."
Pond comments, "what's been so surprising is just how transmissible SARS-CoV-2 has been from the outset. Usually viruses that jump to a new host species take some time to acquire adaptations to be as capable as SARS-CoV-2 at spreading, and most never make it past that stage, resulting in dead-end spillovers or localised outbreaks."
Studying the mutational processes of SARS-CoV-2 and related sarbecoviruses (the group of viruses SARS-CoV-2 belongs to from bats and pangolins), the authors find evidence of fairly significant change, but all before the emergence of SARS-CoV-2 in humans. This means that the 'generalist' nature of many coronaviruses and their apparent facility to jump between hosts, imbued SARS-CoV-2 with ready-made ability to infect humans and other mammals, but those properties most have probably evolved in bats prior to spillover to humans.
Joint first author and PhD student Spyros Lytras adds, "Interestingly, one of the closer bat viruses, RmYN02, has an intriguing genome structure made up of both SARS-CoV-2-like and bat-virus-like segments. Its genetic material carries both distinct composition signatures (associated with the action of host anti-viral immunity), supporting this change of evolutionary pace occurred in bats without the need for an intermediate animal species."
Robertson comments, "the reason for the 'shifting of gears' of SARS-CoV-2 in terms of its increased rate of evolution at the end of 2020, associated with more heavily mutated lineages, is because the immunological profile of the human population has changed." The virus towards the end of 2020 was increasingly coming into contact with existing host immunity as numbers of previously infected people are now high. This will select for variants that can dodge some of the host response. Coupled with the evasion of immunity in longer-term infections in chronic cases (e.g., in immunocompromised patients), these new selective pressures are increasing the number of important virus mutants.
It's important to appreciate SARS-CoV-2 still remains an acute virus, cleared by the immune response in the vast majority of infections. However, it's now moving away faster from the January 2020 variant used in all of the current vaccines to raise protective immunity. The current vaccines will continue to work against most of the circulating variants but the more time that passes, and the bigger the differential between vaccinated and not-vaccinated numbers of people, the more opportunity there will be for vaccine escape. Robertson adds, "The first race was to develop a vaccine. The race now is to get the global population vaccinated as quickly as possible."
INFORMATION:
Research Article
Peer reviewed; Experimental study; Animals
In your coverage please use these URLs to provide access to the freely available articles in PLOS Biology: http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001115
Citation: MacLean OA, Lytras S, Weaver S, Singer JB, Boni MF, Lemey P, et al. (2021) Natural selection in the evolution of SARS-CoV-2 in bats created a generalist virus and highly capable human pathogen. PLoS Biol 19(3): e3001115. https://doi.org/10.1371/journal.pbio.3001115
Funding: DLR is funded by the Medical Research Council (MC_UU_1201412) and Wellcome Trust (220977/Z/20/Z). OAM is funded by the Wellcome Trust (206369/Z/17/Z). SLKP and SW are supported in part by the National Institutes of Health (R01 AI134384 (NIH/NIAID)) and the National Science Foundation (award 2027196). PL acknowledges funding from the European Research Council under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 725422-ReservoirDOCS), the European Union's Horizon 2020 project MOOD (874850), the Wellcome Trust through project 206298/Z/17/Z (The Artic Network) and the Research Foundation -- Flanders (`Fonds voor Wetenschappelijk Onderzoek -- Vlaanderen', G066215N, G0D5117N and G0B9317N). MFB is funded by a grant from the Bill and Melinda Gates Foundation (INV-005517) and by NIH/NIAID Center of Excellence in Influenza Research and Surveillance contract (HHS N272201400007C). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
2021-03-12
Informing how COVID-19 response plans may incorporate digital contact tracing, a model of COVID-19 spread within a simulated French population found that if about 20% of the population adopted a contact tracing app on their smartphones, an outbreak could be reduced by about 35%. If more than 30% of the population adopted the app, the epidemic could be suppressed to manageable levels. Jesús Moreno López and colleagues note that the effectiveness of digital contact tracing would depend on a given population's level of immunity to the virus; the intervention alone would be unable to suppress a COVID-19 epidemic where transmission - and especially asymptomatic transmission - remains high. While many countries have implemented ...
2021-03-12
DURHAM, N.C. -- If you binged on high-calorie snacks and then spent the winter crashed on the couch in a months-long food coma, you'd likely wake up worse for wear. Unless you happen to be a fat-tailed dwarf lemur.
This squirrel-sized primate lives in the forests of Madagascar, where it spends up to seven months each year mostly motionless and chilling, using the minimum energy necessary to withstand the winter. While zonked, it lives off of fat stored in its tail.
Animals that hibernate in the wild rarely do so in zoos and sanctuaries, with their climate controls and ...
2021-03-12
Decades of feminist gains in the workforce have been undermined by the COVID-19 pandemic, which has upended public education across the United States, a critical infrastructure of care that parents -- especially mothers -- depend on to work, according to new research from Washington University in St. Louis.
The research, published in Gender & Society, draws on new data from the Elementary School Operating Status (ESOS) database to show that the gender gap between mothers and fathers in the labor force has grown significantly since the onset of the pandemic in states where schools primarily offered remote instruction.
And if these circumstances continue, it could deliver ...
2021-03-12
Sound sleep plays a critical role in healing traumatic brain injury, a new study of military veterans suggests.
The study, published in the Journal of Neurotrauma, used a new technique involving magnetic resonance imaging developed at Oregon Health & Science University. Researchers used MRI to evaluate the enlargement of perivascular spaces that surround blood vessels in the brain. Enlargement of these spaces occurs in aging and is associated with the development of dementia.
Among veterans in the study, those who slept poorly had more evidence of these enlarged spaces and more post-concussive symptoms.
"This has huge implications for the armed forces as well as civilians," said lead author Juan Piantino, M.D., MCR, assistant professor of pediatrics (neurology) in the ...
2021-03-12
Astronomers have painted their best picture yet of an RV Tauri variable, a rare type of stellar binary where two stars - one approaching the end of its life - orbit within a sprawling disk of dust. Their 130-year dataset spans the widest range of light yet collected for one of these systems, from radio to X-rays.
"There are only about 300 known RV Tauri variables in the Milky Way galaxy," said Laura Vega, a recent doctoral recipient at Vanderbilt University in Nashville, Tennessee. "We focused our study on the second brightest, named U Monocerotis, which is now the first of these systems from which X-rays have been detected."
A paper describing the findings, led by Vega, was published in The Astrophysical Journal.
The system, called U ...
2021-03-12
Water is perhaps Earth's most critical natural resource. Given increasing demand and increasingly stretched water resources, scientists are pursuing more innovative ways to use and reuse existing water, as well as to design new materials to improve water purification methods. Synthetically created semi-permeable polymer membranes used for contaminant solute removal can provide a level of advanced treatment and improve the energy efficiency of treating water; however, existing knowledge gaps are limiting transformative advances in membrane technology. One basic problem is ...
2021-03-12
BOSTON -- SARS-CoV-2, the virus that causes COVID-19, has mutated throughout the pandemic. New variants of the virus have arisen throughout the world, including variants that might possess increased ability to spread or evade the immune system. Such variants have been identified in California, Denmark, the U.K., South Africa and Brazil/Japan. Understanding how well the COVID-19 vaccines work against these variants is vital in the efforts to stop the global pandemic, and is the subject of new research from the Ragon Institute of MGH, MIT and Harvard and Massachusetts General Hospital.
In a study recently published in Cell, Ragon Core Member Alejandro Balazs, PhD, found that the neutralizing antibodies induced by the ...
2021-03-12
Orono, Maine -- The origins of ice age climate changes may lie in the Southern Hemisphere, where interactions among the westerly wind system, the Southern Ocean and the tropical Pacific can trigger rapid, global changes in atmospheric temperature, according to an international research team led by the University of Maine.
The mechanism, dubbed the Zealandia Switch, relates to the general position of the Southern Hemisphere westerly wind belt -- the strongest wind system on Earth -- and the continental platforms of the southwest Pacific Ocean, and their control on ocean currents. Shifts in the latitude of the westerly winds affects the strength ...
2021-03-12
March 12, 2021 - Financial strains like debt or unemployment are significant risk factors for becoming homeless, and even help to explain increased risk of homelessness associated with severe mental illness, reports a study in a supplement to the April issue of Medical Care. The journal is published in the Lippincott portfolio by Wolters Kluwer.
The findings "suggest that adding financial well-being as a focus of homelessness prevention efforts seems promising, both at the individual and community level," according to the new research, led by Eric Elbogen, PhD, of the US Department of Veterans Affairs (VA) National Center on Homelessness and Duke University School of Medicine. The study appears as part of a special issue on ...
2021-03-12
Mantle cell lymphoma is a malignant disease in which intensive treatment can prolong life. In a new study, scientists from Uppsala University and other Swedish universities show that people with mantle cell lymphoma who were unmarried, and those who had low educational attainment, were less often treated with a stem-cell transplantation, which may result in poorer survival. The findings have been published in the scientific journal Blood Advances.
Patients diagnosed with a mantle cell lymphoma (MCL) where the disease has spread receive intensive treatment with cytotoxic drugs and stem-cell transplantation. In a new study, researchers looked at which people are more likely to be offered transplants, and compared survival between those ...
LAST 30 PRESS RELEASES:
[Press-News.org] SARS-CoV-2 jumped from bats to humans without much change
