Culture

A new approach to genomic species delineation could impact policy and lend clarity to legislation for designating a species as endangered or at risk.

The coastal California gnatcatcher is an unassuming little gray songbird that's been at the epicenter of a legal brawl for nearly 28 years, ever since U.S. Fish and Wildlife Service listed it as threatened under the Endangered Species Act.

Found along the Baja California coast, from down south in El Rosario, Mexico to Long Beach, Calif., its natural habitat is the rapidly declining coastal sagebrush that occupies prime, pristine real estate along the West Coast. When this particular gnatcatcher, Polioptila californica, was granted protection, the region's real estate developers went to court to get it delisted.

Central to their argument, which was dismissed in a federal court, was whether it was an independent species or just another population of a more widely found gnatcatcher. This distinction would dictate its threatened status. Evolutionary biologists have developed a new approach to genomic species delineation that improves upon current methods and could impact similar policy in the future.

This approach is based on the fact that in many groups of organisms it can be problematic to decide where one species begins and another ends.

"In the past, when it was challenging to distinguish species based on external characters, scientists relied on approaches that diagnosed signatures in the genome to identify 'breaks' or 'structure' in gene flow indicative of population separation. The problem is this method doesn't distinguish between two populations separated geographically versus two populations being two different species," said Jeet Sukumaran, computational evolutionary biologist at San Diego State University and lead author of a study published May 13 in PlOS Computational Biology.

"Our method, DELINEATE, introduces a way to distinguish between these two factors, which is important because most of the natural resources management policy and legislature in our society rests on clearly defined and named species units."

Typically, scientists will use a range of different methods to identify boundaries between different species, including statistical analysis and qualitative data to distinguish between population-level variation and species-level variation in their samples, to complete the classification of an organism. In cases where it is difficult to sort the variation between individuals into differences due to variation within a species as opposed to between two species, they often turn to genomic data based approaches for the answer. This is when scientists often use a model that generates a population phylogeny, or an evolutionary tree relating different populations.

Sukumaran and co-authors evolutionary biologists L. Lacey Knowles with the University of Michigan, Ann Arbor and Mark Holder with the University of Kansas, Lawrence add a second layer of information to the population phylogeny, to explicitly model the actual speciation process. This allows them to understand how these separate populations sometimes evolve into distinct species, which is the basis for distinguishing between populations and species in the data.

"Our method allows researchers to make statements about how confident they are that two populations are members of the same species,” Holder said. “That is an advance over just making a best estimate of species assignments."

Whether some of the population lineages in the sample are assigned to existing species or classified as entirely new species depends on two factors. One is the age of the population isolation events such as the splitting of an ancestral population into multiple daughter populations, which is how species are "born" in an extended process of speciation. The other is the rate of speciation completion, which is the rate at which the nascent or incipient species "born" from population splitting events develop into true full species.

"We're coming to realize now that many organisms are cryptic species," Sukumaran said. "Many of them are similar looking even though they are actually distinct species separated by many tens or hundreds of thousands or even millions of years of evolution."

This is either due to strong selection pressures to maintain the same morphology, or, more typically, due to very recent speciation resulting in insufficient time for external differences to develop.

"When rivers change course, when terrain changes, previously cohesive populations get fragmented, and the genetic makeup of the two separate populations, now each a population in their own right, can diverge," Sukumaran said. "Eventually, one or both these populations may evolve into separate species, and may (or may not) already have reached this status by the time we look at them.

"Yet individuals of these two populations may look identical to us based on their external appearances, as differences in these may not have had time to 'fix' in either population. This is when we turn to genomic data to help guide us toward deciding whether we are looking at two populations of the same species, or two separate species."

Currently, scientists apply a model based on multispecies coalescent theory to genomic data to identify the disruption of gene flow between different groups of organisms. This disruption is fundamental to species formation, but it can also occur between two different populations as well as two different species.

While scientists agree that it is critical to distinguish between populations and species boundaries in genomic data, there is not always a lot of agreement on how to go about doing it. "If you ask ten biologists, you will get twelve different answers," Sukumaran said.

By modeling the dynamics of speciation itself in the species delimitation analysis, something previous methods did not do, the researchers' approach allows for distinguishing between interpopulation boundaries to gene flow versus interspecies boundaries, based on the predicted pace of the speciation events.

With this framework, scientists can have a better understanding of the status of any species, but especially of species that are members of a species complex -- multiple independent species that all look alike.

Many fields of science and medicine depend on the accurate demarcation and identification of species, including ecology, evolution, conservation and wildlife management, agriculture and pest management, epidemiology and vector-borne disease management etc. These fields also intersect government, legislature and policy, with major implications for the day-to-day lives of broader human society.

The DELINEATE model is a first step in a process that will need to be further refined. Funding for this research came from the National Science Foundation.

SAN FRANCISCO, CA--May 12, 2021--Following the minuscule movements of every cell in a petri dish would be a painstaking task for any human. But teach a set of computer programs to do the job, and they can complete it quickly and even observe things that the human eye would miss.

Scientists at Gladstone Institutes have developed such an approach, which uses "neural nets"--artificial intelligence programs that can detect patterns--to analyze the locations of hundreds of cells growing together in a colony. When they applied the technique to a group of stem cells, the program revealed that a small number of cells act as "leaders," able to direct the movements of their neighbors.

"This technique gives us a much more comprehensive view of how cells behave, how they work cooperatively, and how they come together in physical space to form complex organs," says Gladstone Senior Investigator Todd C. McDevitt, PhD, senior author of a new paper published in the journal Stem Cell Reports.

Clusters of stem cells have the ability to form any tissue in the human body when exposed to the right mixture of signaling molecules. But researchers have a poor understanding of how those cells form patterns in space to eventually give rise to complex three-dimensional organs.

Traditionally, to study how cells move in space over time, cell biologists tag cells with fluorescent molecules that make them easy to track. Then, they watch those cells under a microscope to see how they divide and migrate. However, a human observer can only follow a small handful of cells at a time before it becomes too challenging to distinguish different cells and track their movements. This means scientists often have to extrapolate how an entire colony moves based on the movements of just a few of its members.

In the new paper, McDevitt's group trained three different neural networks to follow the motions of individual cells within colonies of thousands of cells. Each network had its own strengths and weaknesses, and individually none of them outperformed a person. But combined, the three neural networks were slightly more effective at tracking cells--they were able to find 94 percent of all cells in sequential frames, meaning they could follow their movements over time. Humans could only track 90 percent of all cells between frames; a scientist trying to follow cell movements could only figure out where nine of every ten cells moved. What's more, the combined neural networks were 500 times faster than a person, averaging 0.35 seconds per frame to identify all cells, while a human averaged about 3 minutes per frame.

When the researchers used the networks to study new colonies of stem cells, they were surprised to see lots more action than previous cell-tracking techniques had identified. While the colonies looked fairly static to the naked eye, the neural networks showed that nearly every cell was on the move--and much of the movement looked random.

"Going in, we didn't really expect there to be that much cell motion, so we had to come up with new approaches to understand the apparent chaos of the cells," says Gladstone Graduate Student David Joy, first author of the new paper.

Cells nearest the edges of each colony moved the most, McDevitt's group discovered. And cells tended to start and stop more than researchers would have guessed--on average, each cell moved for approximately 15 minutes, followed by a quiescent, motionless 10-minute period before another active phase began.

The researchers went on to show how changing the conditions of the cells' environment--by exposing the cells to different nutrients or drugs--can change how cells move. They also used the neural networks to track stem cell colonies over 24 hours as they began to form the multiple layers of different cell types that appear in an early embryo. The team found that cells have a wide range of movement profiles.

"Some cells move with a lot of persistence in once direction, while others move around and around but never get far from where they started," says Ashley Libby, PhD, a former graduate student in McDevitt's lab who helped lead the work. The diversity surprised the team; they had expected most cells to follow similar patterns of movement, she says.

What's more, some cells acted as "leaders" while others behaved more like "followers," the researchers say. The motion of a small number of cells spread outward to their neighbors, eventually shifting the dynamics of the entire colony. It's a pattern that wouldn't have been obvious if just a few cells had been tracked over time by a human observer.

The new findings are just a small sampling of the kinds of observations that will be possible as artificial intelligence approaches are applied to cell tracking, says McDevitt. And the knowledge that comes from these future experiments will be useful to researchers trying to coax cells to come together into complex organoids and organs--for both research and therapeutic purposes.

"If I wanted to make a new human heart right now, I know what types of cells are needed, and I know how to grow them independently in dishes," says McDevitt, who is also a professor of bioengineering and therapeutic sciences at UC San Francisco. "But we really don't know how to get those cells to come together to form something as complex as a heart. To accomplish that, we need more insights into how cells work cooperatively to arrange themselves."

As a next step, McDevitt's team is planning future studies that use the neural networks to analyze movements within stem cell cultures that have genetic mutations, to help show the effect of different genes on cell organization.

Numerous compelling evidences from astroparticle physics and cosmology indicate that the major matter component in the Universe is dark matter, accounting for about 85% with the remaining 15% is the ordinary matter. Nevertheless, people still know little about the dark matter, including its mass and other properties. Many models predict dark matter particles could couple to ordinary particle at weak interaction level, so it is possible to capture the signal of dark matter particle in the direct detection experiment. The scientific goals of the China Dark matter Experiment (CDEX) are on direct detection of light dark matter and neutrino-less double beta decay with p-type point contact germanium (PPCGe) detectors at the China Jinping Underground Laboratory (CJPL). The measurable energy spectra induced by the elastic scattering between dark matter particles and target nucleons in CDEX detector system could give us the information of dark matter mass, spin and other properties.

The analysis of the current dark matter experiments is usually model dependent, and many models beyond the standard model have predicted the existence of dark matter, such as super-symmetry model and extra-dimension model. Due to the variety of physics models, the constraints obtained from same experimental data cannot be applied directly to other models, which brings complications to physical interpretations. Cosmology observations have verified that the major part of dark matter is the non-relativistic cold dark matter, and as a result, the momentum transfer in the scattering process between dark matter particles and nucleons is only about hundreds of MeV, much lower than the electroweak scale (~250 GeV). It is therefore suitable to use effective field theory to analyze the interaction between dark matter and ordinary matter. Two alternative schemes have been proposed in recent years to study different possible interactions, namely non-relativistic effective field theory (NREFT) and chiral effective field theory (ChEFT). An effective theory contains all possible interactions allowed by given symmetric principles, so it can model-independently reduce the complicacy of analysis.

In the dark matter direct detection experiments, what are mostly focused on are the spin-independent (SI) and spin-dependent (SD) scattering analysis, while EFT can give more momentum-dependent or velocity-dependent interaction which are not taken into consideration usually. Benefiting from the low electrical noise of PCCGe, the analysis threshold of CDEX-1B and CDEX-10 both reach 160 eV, which can largely improve the detection sensitivity for light dark matter.

Based on the data set of CDEX-1B and CDEX-10, CDEX collaboration presents new limits for the couplings of WIMP-nucleon arising from NREFT and ChEFT. In the nonrelativistic effective field theory approach, they improve over the current bounds in the low mχ region. In the chiral effective field theory approach, they for the first time extended the limit on WIMP-pion coupling to the mχRelated results have been published online entitled "First experimental constraints on WIMP couplings in the effective field theory framework from CDEX" on Science China-Physics, Mechanics & Astronomy (Sci. China-Phys. Mech. Astron. 64, 281011 (2021))[1]. Prof. Y. F. Zhou from the Institute of Theoretical Physics, Chinese Academy of Sciences wrote a review article for this publication[2].

The operation and analysis of CDEX-1B and CDEX-10 are coming to the end, and the next generation of experiments CDEX-100/CDEX-1T are under preparation now. The lower background level and improvement of PPCGe performance can raise the sensitivity of direct detection experiment. While the next generation experiment of CDEX can discover dark matter remains unknown, but the mystery of dark matter will encourage more and more researchers to pursue its studies until the day when this profound mystery of the Universe will be solved.

The evolution of ankle and foot bones into different shapes and sizes helped mammals adapt and thrive after the extinction of the dinosaurs, a study suggests.

A surge of evolution following the mass extinction 66 million years ago enabled mammals to diversify and prosper during a period of major global change, researchers say.

Analysis of bones that form part of the ankle and the heel of the foot reveal that mammals during this time - the Paleocene Period - were less primitive than previously thought.

Palaeontologists from the University of Edinburgh made the discovery by comparing the anatomy of Paleocene mammals with species from the earlier Cretaceous Period and those that exist today.

They analysed foot and ankle bone measurements - which provide insights into animals' lifestyle and body size - of 40 Paleocene species. The team contrasted the results with data from living mammal species and mammals that existed during the Cretaceous Period.

Their findings show that Paleocene mammals had stockier, more muscular builds than those from the Cretaceous or present day. The animals' joints were also very mobile, supported by ligaments and tendons - rather than bony features as in some living mammals - which the team hypothesise enabled them to adapt and evolve more rapidly following the extinction.

Many species' ankles and feet closely resembled those of ground-dwelling and burrowing mammals that exist today, indicating that these lifestyles were key to surviving and thriving after the mass extinction, which was caused by an asteroid impact.

The ability to dig underground, for example, is likely to have helped mammals survive the initial devastation, while a loss of tree habitats after the extinction period may have favoured ground-dwelling species, the team says.

The study is published in the journal Proceedings of the Royal Society B. An Open Access version of the paper is available here: https://www.research.ed.ac.uk/en/publications/quantitative-assessment-of-tarsal-morphology-illuminates-locomoto. It was funded by a Marie Curie Career Integration Grant, the Natural Environment Research Council, National Science Foundation and European Research Council.

Dr Sarah Shelley, from the University of Edinburgh's School of GeoSciences, who led the study, said: "At the core of our study, we wanted to figure out what Paleocene mammals were doing in terms of their anatomy and how this related to aspects of their lifestyle and evolution in the wake of the dinosaur extinction. Paleocene mammals have this tendency to combine unusual mish-mashes of anatomy but are often seen as 'archaic' and unspecialised precursors to living mammal groups. What we found was this incredible diversity - they're adapting and evolving their robustly built bodies in ways that are different to living mammals. Our results show one of the many ways mammals were able to adapt and thrive following the catastrophic devastation of the end-Cretaceous extinction."

Arizona! The sunsets. The saguaros. The snakes.

All of them are part of life in the sunny Southwest, but keeping cool when the latter is holed up in a golf bag, air compressor or swimming pool pump house is a big ask for a lot of people.

Not as big as you'd think, however.

The first study to analyze snake removals in a social-ecological context was recently published by an Arizona State University conservation biologist working with a local rattlesnake removal company.

"I think one of the surprises was that people don't hate snakes," said researcher Heather Bateman of the College of Integrative Sciences and Arts. "A lot of them responded that the snakes are important to the desert ecosystem and the snake belongs in the desert, just not in my garage."

Snakes were most frequently removed from neighborhoods with wealthier and more highly educated residents, a greater proportion of Hispanic residents and recently constructed homes.

Bateman studied the records from 2,000 snake removals in metro Phoenix between 2018 and 2019. More than 68% of removals were venomous Western diamondback rattlesnake, the most common species in the area.

The contact zone for rattlesnakes and other species tends to be on the Valley fringes, said Bryan Hughes, owner of Rattlesnake Solutions. He gets the most calls from north of the Loop 101 freeway in Phoenix, Scottsdale and Cave Creek.

"A lot of that (area) has this very deep penetration zone where you can find rattlesnakes miles into areas that have been developed," Hughes said. "And that's just because of the way that the properties are developed. They leave natural waterways in place. They tend to use xeric landscaping on larger lots."

They also turn up in Phoenix around the mountain preserves. "That contact zone is razor thin," he said. "It's basically just that first row of houses that surround those parks."

Snake removal was high in neighborhoods with high income, the study found. But in high-income and high-education areas, snake removal was lower.

"That might indicate that there is an understanding that snakes play these important roles in ecosystems and maybe they're OK to be left in place or handled a different way," Bateman said. "Maybe it's because ... they understand the positive benefits of snakes and are less concerned and maybe decide against removal."

Snakes rarely get inside houses. If they do, they came in through an open door, Hughes said.

"We do have a lot of people that move here from cooler environments where a nice spring day means you leave the back patio unlocked and open a little bit and rattlesnakes will come in there occasionally that way, but very rarely," he said. "Most of the time when we get snakes at people's houses, it's in the backyard or the front yard where a lot of the landscaping, as the paper shows, is something that can be useful or mimics in some ways native landscaping that they use."

Hughes grew up in Idaho catching snakes for fun. He moved to Arizona 22 years ago.

"My interest in snakes changed from garter snakes to rattlesnakes at that point," he said.

He has been in business for about 10 years. He has about 25 employees positioned around the Valley and Tucson, who can usually show up for a call in half an hour.

"We have a massive data set just because we're out there and able to collect a lot of information," he said. "So I'm really excited about this type of collaboration."

The amount of data Hughes had on hand was a delight to Bateman.

"There's a lot that ecologists can gain and by partnering with the business community," she said. "What a great relationship to pair scientists with this business who also is using science. They understand their snakes. And they're contributing to what we know just about the natural history of these species. ... If I look at other sources of information of snakes in Maricopa County, I can go to the scientific literature and there's a couple of papers. And they studied snakes for years. They used road writing surveys (where biologists walk or drive down roads and record what they find) and other types of surveys. And they found on the order of hundreds of snakes, not thousands of snakes."

The published study will be of use to Hughes in his work as well.

"One of the biggest things that I saw that is going to have a lot of use for me just dealing with the public is the fact that how people felt about snakes was not meaningfully impacted by whether or not it's an area that a lot of snakes are removed," he said. "I've always thought that our culture has a lot to do with whether or not people feel positively or negatively about snakes. And a lot of what's in there suggests that, which gives me a lot of lessons about how, when I'm talking to somebody that is scared of snakes, how I can talk with them and how I might be able to change their mind."

The Indian public blamed foreigners, minority groups and doctors for the rapid spread of COVID-19 across the country during the first wave, due to misinformation, rumour and long-held discriminatory beliefs, according to an international study led by Monash University.

This resulted in people refusing to get tested for fear of humiliation or public reprisals, which included attacks on Muslims and health care workers.

However, when presented with accurate and reliable information about the virus spread, the Indian public back-pedalled on those negative sentiments and were more likely to get tested and seek medical help, highlighting the importance of health advice from credible sources.

A world-first study by researchers in the Monash Business School, Indian Institute of Technology Kanpur and University of Southampton found the prevalence of accurate information decreased the stigmatisation of COVID-19 patients and reduced the belief that infection was confined to religious minorities, lower-caste groups and frontline workers.

Led by Professor Asad Islam, Director of the Centre for Development Economics and Sustainability in the Monash Business School, the study surveyed 2,138 people across 40 localities in the Indian state of Uttar Pradesh on their views about spread of COVID-19.

Ninety-three per cent of respondents blamed foreigners for the spread of COVID-19, while 66 per cent also blamed the Muslim population. Surprisingly, 34 per cent and 29 per cent of people blamed health care workers and police respectively for failing to contain the virus spread.

The social and physical consequences of stigmatisation were found to be severe, as those with symptoms refused to step forward and get tested for fear of public humiliation.

Other examples included the refusal of non-Hindu doctors and patients to have a dignified burial; attacks on Muslims during and after religious events; health care workers being assaulted and asked to vacate their residences due to fear of virus spread; and incidents of COVID-19 patients leaving self-isolation early.

As India comes to grips with a devastating second wave, with an average of 350,000 new cases and 4,000 deaths daily, researchers say these incidents during the first wave are happening again.

"We believe the results are as relevant today, as widespread stigmatisation is visible even during this wave," Dr Islam said.

"Cases of stigmatisation during the second wave have resulted in doctors being verbally abused and prevented from taking a lift in their own residential flat, old parents being abandoned, several patients fleeing medical facilities across the country, and dead bodies being dumped in rivers.

"Most importantly, we found that stigmatisation of COVID-19 can have negative public health implications as it may lead people to avoid getting tested and respecting prevention measures. This is essential if India is to get on top of this second wave."

During the study, which took place in June 2020 at the height of the first wave, researchers surveyed individuals by phone and followed up with a randomised controlled test. The treatment group received information about COVID-19 and preventive strategies.

Researchers followed up with participants about one month later to assess if the information intervention was effective in improving knowledge about the transmission and prevention of COVID-19.

More than half of the participants who received the information brief were less likely to believe that any particular group was to be blamed for the spread of the disease and thus reduced stigmatisation of COVID-19 patients, frontline workers (health care workers, sanitary workers, and the police), and marginalised groups such as religious minorities.

Furthermore, researchers identified a significant increase in the self-reporting of COVID-related symptoms and subsequent medical treatment in the Indian population, including treatment for mental health. There was a 75 percentage point reduction in stress and anxiety experienced by participants in the treatment group.

An additional 10 per cent of participants reported a greater quality of life as a result of heightened information awareness and consumption.

"Health advice from credible sources in simple language is of utmost importance as individuals are still taking the pandemic lightly, not wearing their masks and are reluctant to get vaccinated due to widespread ignorance and misconception, even when the numbers are soaring," research co-author Associate Professor Liang Choon Wang from the Monash Business School's Department of Economics said.

"Raising awareness and reducing stress and stigmatisation could lead to encouraging vaccination rates, following prescribed quarantine or lockdown guidelines, coming forward and getting tested if symptoms are visible (or in early stages of infection) and getting help at the earliest time."

Traffic noise leads to inaccuracies and delays in the development of song learning in young birds. They also suffer from a suppressed immune system, which is an indicator of chronic stress. A new study by researchers of the Max Planck Institute for Ornithology and colleagues shows that young zebra finches, just like children, are particularly vulnerable to the effects of noise because of its potential to interfere with learning at a critical developmental stage.

Traffic noise is a pervasive pollutant that adversely affects the health and well-being of millions of people. In addition to severe noise-induced diseases in adults, traffic noise has also been linked to learning impairments and language deficits in children. In order to analyse the causal mechanisms connecting chronic noise exposure to cognitive deficiencies, researchers of the Max Planck Institute for Ornithology with colleagues at the University of Paris Nanterre and the Manchester Metropolitan University studied the song learning and immune function of young zebra finches exposed to traffic noise. Like children, songbirds must learn their vocalizations from adult tutors during a sensitive period early in life. Under normal conditions, the songs of the finches become stable and stereotyped at an age of around 90 days, and remain the same for the rest of their adult life, a process called "crystallization".

For the study, the researchers raised male zebra finch chicks in two groups. During their sensitive song learning period, the chicks in both groups were tutored with recorded song of adult males. In one group, the birds were additionally exposed to traffic noise that had been recorded in bird habitats close to busy roads in the city of Munich, Germany. The scientists monitored the singing activity of each male and compared their song development and learning success. Furthermore, they measured the immune responses of the chicks while they grew up.

Noise weakens immune response

The researchers found that juvenile zebra finches exposed to realistic levels of city noise had weaker immune responses than chicks from quiet nests, suggesting that noise was a source of chronic stress in these young birds. Furthermore, the birds in the noise treatment were significantly delayed in their vocal development - crystallizing their songs more than 30% later than controls, and with significantly lower accuracy in their song learning. "Our findings indicate that young songbirds, just like human children, are particularly vulnerable to the effects of noise because of its potential to interfere with learning at a critical developmental stage", says Henrik Brumm, who led the international research project.

The results of the study suggest that traffic noise even has the potential to affect the cultural evolution of bird song since noise-induced copying errors are likely to accumulate as song passes from one bird to another. "Our paper marks a breakthrough in the study of the effects of anthropogenic noise," Sue Anne Zollinger of the research team concludes, "it establishes bird song as an experimental paradigm for future studies on noise-related cognitive and developmental impairments, especially in regard to vocal learning deficiencies and speech development".

New Orleans, LA - Research conducted by an international team of scientists discovered a mechanism that leads to Herceptin resistance, representing a significant clinical obstacle to successfully treating HER2-positive breast cancer. They also identified a new approach to potentially overcome it. The work is published online in Nature Communications, available here.

"This work attempts to understand why some HER2-positive breast cancer patients do not benefit from treatment with Herceptin, which is a generally effective HER2-targeted therapy," explains Bolin Liu, MD, Professor of Genetics at LSU Health New Orleans' School of Medicine and Stanley S. Scott Cancer Center.

The researchers found increased signaling by IGF2/IRS1 (genes involved in regulating cell proliferation, growth, migration, differentiation and survival) in the HER2-positive breast cancer cells poorly responding to Herceptin. Further studies showed that disruption of a negative feedback loop formed by an important protein, FOXO3a, and several miRNAs that are controlled by FOXO3a causes abnormal activation of the IGF2/IRS1 signal, thereby leading to Herceptin resistance.

"Resistance to Herceptin frequently occurs and currently represents a major clinical challenge for successful treatment of HER2-positive breast cancer," notes Dr. Liu. "Data presented in the study not only improve our understanding of the molecular mechanism through which IGF-1R signaling activation leads to Herceptin resistance, but also promote identification of precision therapies to reverse the resistance phenotype."

The researchers write, "Breast cancer is the leading cause of cancer-related deaths in women worldwide. HER2-positive breast cancer is defined as a breast cancer subtype with amplified and/or overexpressed HER2 (or erbB2) gene. Amplification/overexpression of HER2 is observed in approximately 20-25% of breast cancers and is significantly associated with poor prognosis in breast cancer patients. Herceptin (or trastuzumab), a humanized anti-HER2 monoclonal antibody (Ab), is an effective HER2-targeted therapy against early and metastatic HER2-positive breast cancers. It has dramatically improved the survival of breast cancer patients with HER2-positive tumors, but not all HER2-positive breast cancers respond to Herceptin-based regimens. To date, we lack validated biomarkers predictive for Herceptin response."

"Our results may provide new avenues to identify useful biomarkers predictive for Herceptin efficacy and facilitate the development of novel approaches to enhance HER2-targeted therapy, thereby improving the survival of refractory breast cancer patients," Dr. Liu concludes.

People who work nontraditional work hours, such as 11 p.m.-7 a.m., or the "graveyard" shift, are more likely than people with traditional daytime work schedules to develop a chronic medical condition -- shift work sleep disorder -- that disrupts their sleep. According to researchers at the University of Missouri, people who develop this condition are also three times more likely to be involved in a vehicle accident.

"This discovery has many major implications, including the need to identify engineering counter-measures to help prevent these crashes from happening," said Praveen Edara, department chair and professor of civil and environmental engineering. "Such measures can include the availability of highway rest areas, roadside and in-vehicle messaging to improve a driver's attention, and how to encourage drivers who may have a late-night work shift to take other modes of transportation, including public transit or ride-share services."

Edara, one of the authors on the study, said the analysis was based on data collected from a real-world driving study for the second Strategic Highway Research Program established by the U.S. Congress.

As the demand for 24/7 business operations has increased in recent years to meet customer needs during all hours of the day and across multiple time zones, the traditional work day -- once defined as 9 a.m.-5 p.m. -- has shifted for many people to include evening and night shifts, causing sleeping difficulties and leading to shift work sleep disorder. Edara said he was surprised to see shift work sleep disorder increase the risk of a traffic crash by nearly 300%, as compared to both sleep apnea and insomnia, which both increased the risk of a crash by approximately 30%.

Edara said previous studies have shown sleep disorders increase the risk for a traffic crash, but the majority of these studies were conducted in a controlled environment, such as a laboratory driving simulator. He believes this real-world data now validates those efforts.

"In the past, researchers have studied sleep disorders primarily in a controlled environment, using test-tracks and driving simulators," Edara said. "Our study goes a step further by using actual observed crash and near-crash data from approximately 2,000 events occurring in six U.S. states. We've known for a while now that sleep disorders increase crash risk, but here we are able to quantify that risk using real world crash data while accounting for confounding variables such as roadway and traffic characteristics."

Edara said some of the limitations of their study include not having data for fatal crashes, and no formal measurement to define drowsiness.

Putting a spotlight onto a national problem

In the United States, the National Transportation Safety Board, or NTSB, is the federal agency that investigates major traffic accidents. Each year, they issue an annual "most wanted list" of safety improvements, and their 2019-2020 list includes "screening and treating obstructive sleep apnea" among the top 10 topic areas.

Edara said he hopes that by showing how big of a risk there is for traffic crashes caused by excessive daytime sleepiness, the researchers can help draw additional attention toward finding ways to keep people safe behind the wheel, including taking the driver out of the equation with ride-sharing options and automated vehicles. He said the ideal next step in this research would be to partner with medical professionals who have expertise in this area to better understand why this is happening.

"We want to partner with public health and medical professionals whose expertise is in sleep-related research to better understand why this is happening," Edara said. "That will also allow us to explore what kind of countermeasures we can develop and test to improve the overall safety of these drivers and the other motorists around them."

Writing in the New England Journal of Medicine, a trio of science communication researchers proposes to treat the Covid-19 misinformation "infodemic" with the same methods used to halt epidemics.

"We believe the intertwining spreads of the virus and of misinformation and disinformation require an approach to counteracting deceptions and misconceptions that parallels epidemiologic models by focusing on three elements: real-time surveillance, accurate diagnosis, and rapid response," the authors write in a Perspective article.

"The word 'communicable' comes from the Latin communicare, to share, to make common," said David Scales, M.D., Ph.D., of Weill Cornell Medical College and chief medical officer of the science-promoting nonprofit organization Critica. "What are the similarities between all the information shared on social media and communicable diseases? It's a helpful analogy in thinking through both of them."

Scales co-authored the article with Jack Gorman, M.D., president and chair of Critica, and Kathleen Hall Jamieson, Ph.D., director of the Annenberg Public Policy Center (APPC) of the University of Pennsylvania.

The publication comes as APPC has released national survey data finding that while some 75% of the American public views the approved Covid-19 vaccines as effective and safer than getting Covid-19, about 15% is not sure whether this is true and 10% to 12% thinks this is false.

A misinformation 'superspreader' event

Better infodemic-surveillance methods and a rapid response, the authors write, could have prevented the "superspreader" event that began on October 12, 2020, when the conservative website The Federalist misread a report by the Centers for Disease Control and Prevention (CDC) and reported that "masks and face coverings are not effective in preventing the spread of Covid-19." The following night, Fox News' Tucker Carlson mistakenly told his over 4 million viewers that 85% of the people infected by Covid-19 in July 2020 had been wearing a mask.

"The superspreading escalated," the researchers wrote, "when President Donald Trump echoed the same mischaracterization to more than 13 million viewers of a nationally televised October 15 town hall." Had The Federalist article been immediately and widely countered, the town hall moderator, NBC journalist Savannah Guthrie, might have been better equipped to counter the inaccurate claim than to say that Trump's characterization of the study was incorrect.

Detecting and halting misinformation

In their article, the authors recommend a series of steps to "halt such misinformation cascades":

Surveillance. Since "an overwhelming amount of misinformation and disinformation circulates on social media," sensitive surveillance systems need to be triggered before information goes viral. Companies such as Facebook should provide researchers with de-identified data on the spread of misinformation. "Lack of access to such data is the equivalent of a near-complete blackout of epidemiologic data from disease epicenters," the researchers said. If one were to conduct syndromic disease surveillance using Google, Scales said, "you could see if doctors are searching for Tamiflu, which would be highly correlated with a flu outbreak. You don't have to wait for CDC influenza data but can search for things that are correlated with the disease that show up sooner."

Diagnosis. "Just as scientists need to be able to distinguish one disease from another, infodemiologists need to distinguish different types of misinformation," said Jamieson, APPC's director. The Annenberg Public Policy Center has introduced a taxonomy featured in the NEJM article of categories of mis- and disinformation related to Covid-19 and vaccination. The part of the taxonomy regarding masking, for example, covers five types of misinformation: distortions of scientific findings; assertions that masks' effectiveness has not been proven; claims that masks are ineffective; suggestions that masks increase health risks; and conspiracy theories about masks. "Knowing the type of misinformation that is circulating allows us to develop strategies for buffering audiences from deceptions or misconceptions and, when necessary, to deploy a rapid-response system to rebut and displace inaccurate claims before they take hold," the authors wrote.

Response. Rapid epidemiological response consists of containment and treatment by medical personnel. So-called infodemiologists, modeled after the CDC's Epidemic Intelligence Service officers, can counteract misinformation in traditional media sources and online, the researchers say. Just as few people were trained in CPR a few decades ago but many are today, Scales said many people could be trained in evidence-based ways to counter misinformation. "The goal is to have people ready and trained so they can spring into action when a communication emergency comes up," he said. Critica, a nonprofit organization seeking to center the role of science in making rational health decisions, is among numerous organizations, such as New York State's Citizen Public Health Training Program, training infodemiologists to do this work. Critica's focus is not on those who are staunchly opposed to the vaccines but those who are susceptible to misinformation and vaccine-hesitant.

About 15% of Americans unsure about vaccines

A national probability APPC survey released this week of 1,941 people finds that 74% of the U.S. public says that the authorized Covid-19 vaccines are effective and 75% says the vaccines are safer than getting Covid-19. About 15% is unsure whether these statements are true, a potentially persuadable group that is larger than those deniers who incorrectly say that the statements are false. Read the survey.

Identifying the various kinds of mistaken beliefs is critical to halting their proliferation.

"To make it possible to effectively interdict viral deception we not only need reliable means of finding it but also the wherewithal to predict when, where, and how it will spread," Jamieson noted. "Just as scientists need to be able to distinguish one disease from another, infodemiologists need to distinguish different types of misinformation."

In the NEJM article, the authors argue for a broad approach to combat misinformation.

"Our model will be more effective for people intrigued by misinformation but not yet under its thrall than for committed acolytes sequestered in echo chambers. But the model's strength, like that of epidemiology, is in recognizing that effective prevention and response requires mutually reinforcing interventions at all levels of society, including enhancing social-media algorithmic transparency, bolstering community-level norms, and establishing incentives for healthier media diets."

"The Covid-19 Infodemic - Applying the Epidemiologic Model to Counter Misinformation," was published in The New England Journal of Medicine on May 12, 2021.

Critica is a nonprofit organization whose mission is to promote the public's acceptance of scientific consensus, counteract misinformation about science and health, and increase the use of scientific evidence in public policymaking. Visit us at http://www.criticascience.org.

The Annenberg Public Policy Center was established in 1993 to educate the public and policy makers about communication's role in advancing public understanding of political, science, and health issues at the local, state, and federal levels.

New research led by the University of Kent has found that people fail to recognise the role of factory farming in causing infectious diseases.

The study published by Appetite demonstrates that people blame wild animal trade or lack of government preparation for epidemic outbreaks as opposed to animal agriculture and global meat consumption.

Scientists forewarned about the imminence of global pandemics such as Covid-19, but humankind failed to circumvent its arrival. They had been warning for decades about the risks of intensive farming practices for public health. The scale of production and overcrowded conditions on factory farms make it easy for viruses to migrate and spread. Furthermore, the common practice of feeding antibiotics to farmed animals promotes antimicrobial resistance, threatens public health.

With the focus now on the need to prevent future pandemics and zoonotic diseases, it is critical that there is more understanding on the causes and risks posed by animal agriculture.

This study led by Dr Kristof Dhont (Kent), alongside Dr Jared Piazza (Lancaster University) and Professor Gordon Hodson (Brock University), explored public understanding and opinion to determine where people place the blame of zoonotic disease outbreaks.

Findings show that as well as failing to recognise the detrimental role of factory farming, those who are highly committed to eating meat struggle to acknowledge global meat consumption as a link to the problem. Even after reading about the risks of factory farms in the spread of disease, committed meat eaters were still less convinced of policies to change or ban factory farming than of policies aimed at better preparing for pandemics. Yet, when reading the same information about wild animal markets, they endorsed policies to reduce, regulate, or ban wild animal markets.

Dr Dhont said: 'As world populations swell, our dependence upon meat is likely to grow, making it increasingly pressing to come to grips with the detrimental role of intensive farming and take action to turn the tide. Undoubtedly, humankind needs to be better prepared to handle infectious disease outbreaks - which we are edging closer towards. However, it is vital to identify and uproot the causes of infectious diseases.

'Appetite for meat can be a stumbling block for considering the role of animal agriculture in the spread of zoonotic disease. Meat is a highly enjoyable product for many, a factor inhibiting us from taking actions towards a safer future.

'Solutions to this problem will require policy changes and personal sacrifices, akin to dealing with the looming climate emergency.'

HOUSTON - Cytokine-activated natural killer (NK) cells derived from donated umbilical cord blood, combined with an investigational bispecific antibody targeting CD16a and CD30 known as AFM13, displayed potent anti-tumor activity against CD30+ lymphoma cells, according to a new preclinical study from researchers at The University of Texas MD Anderson Cancer Center.

The findings were published today in Clinical Cancer Research, a journal of the American Association for Cancer Research. These results led to the launch of a Phase I clinical trial to evaluate the combination of cord blood-derived NK cells (cbNK cells) with AFM13 as an experimental cell-based immunotherapy in patients with CD30+ lymphoma.

"Developing novel NK cell therapies has been a priority for my team at MD Anderson to address unmet needs for the treatment of both hematologic cancers and solid tumors," said senior author Katy Rezvani, M.D., Ph.D., professor of Stem Cell Transplantation and Cellular Therapy. "This preclinical work provided proof of principle for NK cells precomplexed with AFM13, suggesting that they can effectively eliminate lymphoma cells expressing CD30 and warrant further clinical testing."

Natural killer cells are part of the innate immune system and work naturally to eliminate cancer cells in the body. However, they have limited persistence on their own, and tumors can develop mechanisms to evade NK cells, Rezvani explained. Therefore, her research team has worked to develop approaches to enhance the anti-tumor efficacy of NK cells.

Affimed's AFM13 is a proprietary bispecific antibody designed to bind to CD16a on NK cells and CD30 on lymphoma cells. Initial studies on NK cells isolated from the blood of patients with Hodgkin lymphoma found that AFM13 formed a stable complex with NK cells and could induce NK cell-mediated killing of CD30+ cells. However, the activity of these cells was modest, leading the researchers to evaluate alternative NK cell sources.

Further experiments suggested that cbNK cells, isolated from umbilical cord blood donations made to the MD Anderson Cord Blood Bank, displayed consistent and improved activity against lymphoma with AFM13 relative to other NK cell sources. The researchers were able to further stimulate the anti-tumor immune activity of cbNK cells by pre-activation with a combination of the cytokines IL-12/15/18.

In animal models, pre-activated and expanded cbNK cells complexed with AFM13 resulted in improved tumor control and survival relative to controls, with minimal side effects observed.

"These findings suggest that, in animal models, ex vivo pre-activated and expanded cord blood-derived NK cells complexed with AFM13 were able to safely eliminate CD30+ lymphoma cells," Rezvani said. "We look forward to learning if this investigational therapy may provide benefits to patients with advanced lymphoma in the ongoing clinical trial."

Boston - Pregnant women with symptomatic COVID-19 have a higher risk of intensive care unit admissions, mechanical ventilation and death compared to non-pregnant reproductive age women. Increases in preterm birth and still birth have also been observed in pregnancies complicated by the viral infection. The Centers for Disease Control and Prevention (CDC) recommended that people who are pregnant may choose to be vaccinated at their own discretion with their healthcare provider. However, pregnant and lactating women were not included in Phase 3 vaccine efficacy trials; thus, data on vaccine safety and immunogenicity in this population is limited.

In a new study from Beth Israel Deaconess Medical Center (BIDMC), specialists in the Department of Obstetrics and Gynecology and the Center for Virology and Vaccine Research evaluated the immunogenicity of COVID-19 mRNA vaccines in pregnant and lactating women who received either the Pfizer or Moderna COVID-19 vaccines. The researchers found that both vaccines triggered immune responses in pregnant and lactating women. Further analyses revealed that maternal vaccine antibodies are transferred into infant cord blood and breast milk. The team's findings appear today in the Journal of the American Medical Association.

"Our study supports the use of vaccines in pregnant and lactating individuals. The vaccine-elicited antibodies we detected in both infant cord blood and breast milk suggest that vaccinating pregnant mothers may potentially protect infants from COVID-19 infection," said lead author Ai-ris Y. Collier, MD, a Maternal-Fetal Medicine specialist at BIDMC. "Future research should focus on determining the timing of vaccination that optimizes delivery of antibodies through the placenta and breast milk to newborns."

Collier and colleagues conducted an exploratory, descriptive study of 103 women, ages 18-45, who received an mRNA COVID-19 vaccine (54 percent received Pfizer; 46 percent received Moderna). The scientists found similar levels of vaccine-induced antibody function and T cell responses in all non-pregnant, pregnant and lactating women after their second vaccine dose. Additionally, both pregnant and non-pregnant women who received the mRNA vaccines developed cross-reactive immune responses against the COVID-19 variants of concern B.1.1.7 and B.1.351.

"The COVID-19 mRNA vaccines raised robust immune responses in pregnant, lactating, and non-pregnant non-lactating women," said senior corresponding author Dan. H. Barouch, MD, PhD, Director of the Center for Virology and Vaccine Research at BIDMC. "Additionally, the vaccine-elicited antibody responses were greater than antibody responses seen after COVID-19 infections. These findings add to the emerging data that support the use of these vaccines in pregnant and lactating women."

Despite having been driven nearly to extinction, the California condor has a high degree of genetic diversity that bodes well for its long-term survival, according to a new analysis by University of California researchers.

Nearly 40 years ago, the state's wild condor population was down to a perilous 22. That led to inbreeding that could have jeopardized the population's health and narrowed the bird's genetic diversity, which can reduce its ability to adapt to changing environmental conditions.

In comparing the complete genomes of two California condors with those of an Andean condor and a turkey vulture, UC San Francisco and UC Berkeley scientists did find genetic evidence of inbreeding over the past few centuries, but, overall, a wealth of diversity across most of the genome.

"You need genetic diversity in order to adapt, and the more genetic diversity they (California condors) have, hopefully, the more chance they have to adapt and persist," said Jacqueline Robinson, a UCSF postdoctoral fellow and first author of a paper about the analysis appearing today in the journal Current Biology. "Our study is the first to begin quantifying diversity across the entire California condor genome, which provides us a lot of baseline information and will inform future research and conservation."

The health of the bird's genome is probably due to the species' great abundance in the past. Robinson and her colleagues, including Rauri Bowie, UC Berkeley professor of integrative biology, used statistical techniques to estimate the bird's historical population and found that it was far more abundant across the United States a million years ago than even the turkey vulture, America's most common vulture today. The bird likely numbered in the tens of thousands, soaring and scavenging from New York and Florida to California and into Mexico.

"They have this legacy of high genetic diversity from their former abundance, so I think there is a chance that, with genetic information, we could manage the population going into the future to really maintain the genetic diversity that they do have now and not have any further losses," Robinson said. "You could even choose individual mates to, in a sense, reverse the inbreeding."

Co-author Cynthia Steiner, associate director in conservation genetics for the San Diego Zoo Wildlife Alliance, a nonprofit conservation organization affiliated with the San Diego Zoo, agreed that the genomic information will help refine conservation strategies to maintain genetic diversity and reduce inbreeding. Inbreeding may already be causing an increase among wild condors in a lethal form of dwarfism, chondrodystrophy, and leading to an increase among some birds in the number of tail feathers, from 12 to 14.

"We finally have a genomic resource or tool in-hand for the species that will allow understanding the genetic basis of disease and phenotypic traits, such as chondrodystrophy and the 14-tail feather syndrome, and potentially manage these deleterious traits in the breeding program," Steiner said.

Bowie, an ornithology curator in UC Berkeley's Museum of Vertebrate Zoology (MVZ), hopes to continue working with the San Diego Zoo to analyze the genomes of all 22 original individual condors in the founding population -- the ancestors of all living California condors -- to assess the species' overall genetic diversity. With captive breeding, the aim has always been to mate unrelated condors in order to prevent inbreeding. By generating genome profiles of all individuals of an endangered species, conservationists could more finely tune breeding to weed out any negative health consequences, called inbreeding depression.

"With most endangered species, when you look at their genomes, they have very little genetic diversity left. In other words, they have very little capacity to adapt to change," he said. "That is definitely not the case with the California condor. With these genome data in hand, maybe there is a way to mitigate chondrodystrophy by cross-breeding certain individuals or finding other ways to help them deal with that."

Condor's steady decline

The California condor, Gymnogyps californianus, is considered critically endangered, despite herculean efforts to rescue the species that began in 1987. This involved capturing all wild condors -- 27 at that time -- and breeding them in zoos. The program's success was celebrated in 1991 with the reintroduction of captive-bred condors into the wild. Today, more than 300 individuals roam California, Mexico, Arizona and Utah, while another 200 remain in captivity. With a wingspan larger than any other bird in the United States -- up to 3 meters, or nearly 10 feet, slightly less than that of the Andean condor (Vultur gryphus), its closest relative -- it also is one of the longest-lived birds, often surviving until the age of 60.

Based on the team's genetic analysis of two California condor genomes over the past million years, condor populations gradually fluctuated downward until a precipitate decline began around the time humans settled the Americas 15,000 years ago. This coincides with the disappearance of large land animals -- megafauna -- which were likely exterminated by early inhabitants of America between 10,000 and 12,000 years ago. The carcasses of North American megafauna were undoubtedly a major source of food for these carrion-eating scavengers, and condors may have become restricted to the Pacific Coast because they could take advantage of marine mammal carcasses after land animals became less abundant.

The decline accelerated over the last few hundred years with the rising destruction of condor habitat, increased human poaching and persistent lead poisoning from ingested shotgun pellets.

Small population inbreeding

Robinson, who works in the lab of co-author Jeffrey Wall, a professor in UCSF's Institute for Human Genetics, has focused on genetic studies of small populations where inbreeding increases the incidence of normally rare recessive traits, many of them deleterious. She currently is involved with genetic studies of Mexico's vaquita, the world's smallest porpoise, which is critically endangered in its range within the Gulf of California. She co-authored a report last year that found very low diversity in the vaquita's genome, which is a result of its natural rarity and historically low abundance prior to its recent human-driven population crash, she said.

She embarked on the current study after Bowie collaborated with the San Diego Zoo and the Baylor College of Medicine to produce what he called a "Rolls Royce" version of the condor genome -- a high-quality genome that is a rarity for any wild animal and which rivals the quality of the known genomes of the commercial chicken and the laboratory mouse.

"What I mean by a Rolls Royce genome is that it has very few fragments -- basically, all the chromosomes are intact," she said. "With that, you can get a really good assessment of not only how much genetic diversity there is, but how it is distributed across the genome. And that is really helpful if you are trying to find genes that are related to disease or if you are interested in things that are important for enabling condors to do what they do -- the adaptive genes."

Robinson compared Bowie's condor genome, obtained from the blood of an Arizona condor, and the genome of the San Diego Zoo's condor with the genomes of the Andean condor and the turkey vulture (Cathartes aura), which had already been sequenced.

Surprisingly, given the California condor's history, the two genomes contained the highest levels of diversity among all three species.

"Andean condors are somewhat rare, but turkey vultures are extremely abundant, so this result was a bit unexpected, as it doesn't match current population sizes," Robinson said. "Genetic diversity is tied to species abundance, so the high genetic diversity in California condor genomes contrasts starkly with the extremely small number alive today."

Bowie attributes the condor's success at passing through its near-extinction bottleneck while retaining much of its original genetic diversity to the bird's long lifespan and slow reproductive rate, which determine its generation time.

"Even though their numbers dramatically plummeted, because of their generation time they hadn't passed through many generations, so a lot of that genetic diversity was retained," he said.

The California condor project is one piece of Bowie's current focus on genetic diversity among all living and extinct vultures. Graduate student Mackenzie Kirchner-Smith is currently analyzing vulture skulls in the MVZ and UC Museum of Paleontology collections to understand past vulture populations, while Bowie has just launched an effort to sequence the genomes of the world's living species of vulture, in part to understand how the scavenging lifestyle developed independently among three very distinct bird groups.

Robinson hopes to continue with the condor work, as well. Despite having visited condor habitat in the past, she saw her first condor only a few weeks ago when visiting Pinnacles National Park, a popular hangout for condors along the Central California Coast.

"As I was looking at them, I was literally thinking, these almost disappeared during my lifetime. That would have been such a tragedy," she said. "I would say that we shouldn't write off any species just because there may only be a few individuals left. The California condor came back from a population size of just 22 individuals."

Robinson's co-authors, in addition to Bowie, Steiner and Wall, include David Mindell of UC Berkeley's Museum of Vertebrate Zoology. The work was funded in part by the National Science Foundation (DEB-1441652).

TORONTO, ON - A team of evolutionary biologists from the University of Toronto has shown that Anolis lizards, or anoles, are able to breathe underwater with the aid of a bubble clinging to their snouts.

Anoles are a diverse group of lizards found throughout the tropical Americas. Some anoles are stream specialists, and these semi-aquatic species frequently dive underwater to avoid predators, where they can remain submerged for as long as 18 minutes.

"We found that semi-aquatic anoles exhale air into a bubble that clings to their skin," says Chris Boccia, a recent Master of Science graduate from the Faculty of Arts & Science's Department of Ecology & Evolutionary Biology (EEB). Boccia is lead author of a paper describing the finding published this week in Current Biology.

"The lizards then re-inhale the air," says Boccia, "a maneuver we've termed 'rebreathing' after the scuba-diving technology."

The researchers measured the oxygen (O2) content of the air in the bubbles and found that it decreased over time, confirming that rebreathed air is involved in respiration.

Rebreathing likely evolved because the ability to stay submerged longer increases the lizard's chances of eluding predators.

The authors studied six species of semi-aquatic anoles and found that all possessed the rebreathing trait, despite most species being distantly related. While rebreathing has been studied extensively in aquatic arthropods like water beetles, it was not expected in lizards because of physiological differences between arthropods and vertebrates.

"Rebreathing had never been considered as a potential natural mechanism for underwater respiration in vertebrates," says Luke Mahler, an assistant professor in EEB and Boccia's thesis supervisor. "But our work shows that this is possible and that anoles have deployed this strategy repeatedly in species that use aquatic habitats."

Mahler and co-author Richard Glor, from the University of Kansas, first observed anoles rebreathing in Haiti in 2009 but were unable to carry out further observations or experiments. Another co-author, Lindsey Swierk, from Binghamton University, State University of New York, described the same behaviour in a Costa Rican species in 2019. These early observations suggested that rebreathing was an adaptation for diving, but this idea had not been tested until now.

Boccia became interested in aquatic anoles after encountering one in Panama. He began his rebreathing investigations in Costa Rica in 2017 and continued the research in Colombia and Mexico.

As the authors point out, the rebreathing trait may have developed because anoles' skin is hydrophobic -- it repels water -- a characteristic that likely evolved in anoles because it protects them from rain and parasites. Underwater, air bubbles cling to hydrophobic skin and the ability to exploit these bubbles for breathing developed as a result.

While further work is required to understand how the process works in detail, Boccia, Mahler and their co-authors suggest different ways in which rebreathing may function.

In its simplest form, the air bubble on a lizard's snout likely acts like a scuba tank, providing a submerged animal with a supply of air in addition to the air in its lungs. This is what aquatic arthropods like water beetles do to extend the time they can remain submerged.

The researchers also suggest that the rebreathing process may facilitate using air found in a lizard's nasal passages, mouth and windpipe that would otherwise not be used by the lizard in breathing.

The bubble may also help rid waste carbon dioxide (CO2) from exhaled air through a process other researchers have already observed in aquatic arthropods. Those studies concluded that because CO2 is highly soluble in water and because the level of CO2 in the bubbles is higher than in the surrounding water, exhaled CO2 dissolves into the surrounding water rather than being rebreathed.

Finally, the authors speculate that the bubble may act as a gill and absorb oxygen from the water -- again, something already observed in arthropods. Boccia and Mahler are planning further research to confirm if these rebreathing processes are occurring with anoles.

According to Mahler, "This work enriches our understanding of the creative and unexpected ways that organisms meet the challenges posed by their environments. That is valuable in its own right, but discoveries like this can also be valuable to humans as we seek solutions to our own challenging problems."

"It's too early to tell if lizard rebreathing will lead to any particular human innovations," says Boccia, "But biomimicry of rebreathing may be an interesting proposition for several fields -- including scuba-diving rebreathing technology, which motivated our naming of this phenomenon."