Why lists of worldwide bird species disagree

Data gaps and species similarities may lead to undercounting biodiversity

UNIVERSITY OF UTAH

Research News

 

IMAGE: A CHAMÍ ANTPITTA, WHICH WAS RECENTLY SPLIT AS A DISTINCT SPECIES FROM THE RUFOUS ANTPITTA. view more 

CREDIT: ÇA?AN ?EKERCIO?LU

How many species of birds are there in the world? It depends on whose count you go by. The number could be as low as 10,000 or as high as 18,000. It's tough to standardize lists of species because the concept of a "species" itself is a little bit fuzzy.

That matters because conserving biodiversity requires knowing what diversity exists in the first place. So biologists, led by University of Utah doctoral candidate Monte Neate-Clegg of the School of Biological Sciences, set out to compare four main lists of bird species worldwide to find out how the lists differ--and why. They found that although the lists agree on most birds, disagreements in some regions of the world could mean that some species are missed by conservation ecologists.

"Species are more than just a name," Neate-Clegg says. "They are functional units in complex ecosystems that need to be preserved. We need to recognize true diversity in order to conserve it."

The results are published in Global Ecology and Biogeography.

On the origin of species

The definition of a species isn't clear-cut. Some scientists define populations as different species if they're reproductively isolated from each other and unable to interbreed. Others use physical features to delineate species, while yet others use genetics. Using the genetic definition produces many more species, but regardless of the method, gray areas persist.

"Species are fuzzy because speciation as a process is fuzzy," Neate-Clegg says. "It's a gradual process so it's very difficult to draw a line and say 'this is two species' vs. 'this is one species.'"

Also, he says, physical features and genetic signatures don't always diverge on the same timescale. "For example," he says, "two bird populations may diverge in song and appearance before genetic divergence; conversely, identical populations on different islands may be separated genetically by millions of years."

Comparing the lists

At this point in the story, it's time to introduce four lists, each of which purports to include all the bird species in the world. They are:

• The Howard and Moore Checklist of the Birds of the World
• The eBird/Clements Checklist of Birds of the World
• The BirdLife International Checklist of the Birds of the World
• The International Ornithological Community (IOC) World Bird List

"Being active field ornithologists who are always trying to ID bird species means that one is always faced with the issue of some species being on one list but not the other," says Çağan Şekercioğlu, associate professor in the School of Biological Sciences. "So our field experience very much primed us to think about this question and inspired us to write this paper."

The lists have different strengths depending on their application. The BirdLife International list, for example, integrates with the IUCN Red List, which reports on species' conservation status. The IOC list is updated by experts twice a year, Şekercioğlu says. The list is open access with comparisons to other major lists, and changes are documented transparently.

"But as a birdwatcher, I use eBird all the time, which uses the Clements checklist, and that dataset is very powerful in its own right," Neate-Clegg says. "So there is no single best option."

One example of the disagreement between lists might be the common bird Colaptes auratus. The eBird list calls it the northern flicker, a woodpecker. But the BirdLife International list delineates the eastern population as the yellow-shafted flicker and the western population as the red-shafted flicker.

In 2020, Neate-Clegg and his colleagues read a study that compared the raptor species on each list, finding that only 68% of species were consistent among all four lists.

"We thought it would be interesting to investigate taxonomic agreement for all 11,000 bird species," Neate-Clegg says. "More importantly, we wanted to try and work out what species characteristics led to more or less taxonomic confusion."

They began by collecting the most recent version of each list (the IOC checklist is updated biannually, the researchers write, and the Clements and BirdLife lists annually, while Howard and Moore has not been updated since 2014) and trimming them down to exclude subspecies and any extinct species. Using a few other data processing rules, they assigned a single name to every possible species across all four lists. Then the comparisons began.

Where the lists agree and disagree

The researchers found that the four lists agreed on the vast majority of bird species--89.5%. For the remaining 10.5%, then, they started to look for patterns that might explain the disagreement. Some of it was likely geographical. Birds from the well-studied Northern Hemisphere were more likely to find agreement than birds from the relatively understudied Southeast Asia and the Southern Ocean.

Some of it was habitat-based. Agreement was higher for large, migratory species in relatively open habitats.

"I think the most surprising result was that agreement was not lower for highly forest-dependent species," Neate-Clegg says. "We expected these denizens of the rainforest floor to be the most cryptic and hard to study, with more uncertainty on their taxonomic relationships. Yet we found it was actually species of intermediate forest dependency that had lower taxonomic agreement. We believe that these species move about just enough to diverge, but not so much that their gene pools are constantly mixing."

And part of the issue with species classification on isolated islands, such as those in Southeast Asia and the Southern Ocean, was a phenomenon called "cryptic diversification." Although islands can foster species diversification because of their isolation, sometimes two populations on different islands can appear very similar, even though their genes suggest that they've been isolated from each other for millions of years. So, depending on the definition, two populations could count as two species or as only one.

"In addition," Neate-Clegg says, "it's very hard to test the traditional biological species concept on island fauna because we cannot know whether two populations can interbreed to produce fertile young if they are geographically isolated."

Why it matters

So what if some people disagree on species designations? Conservation actions are usually on the species level, Neate-Clegg says.

"If a population on one island goes extinct, people may care less if it's 'just a subspecies,'" he says. "And yet that island is potentially losing a functionally unique population. If it was recognized as a full species it might not have been lost."

Neate-Clegg hopes the study points ornithologists towards the groups of species that merit additional attention.

"We also want conservation biologists to recognize that cryptic diversity may be overlooked," he adds, "and that we should consider units of conservation above and below the species level."

###

Find the full study here.

Ant responses to social isolation resemble those of humans

Social isolation results in changes of behavior and activity of immune and stress genes

JOHANNES GUTENBERG UNIVERSITAET MAINZ

Research News

 

IMAGE: AN ANT OF THE SPECIES TEMNOTHORAX NYLANDERI view more 

CREDIT: PHOTO/©: SUSANNE FOITZIK, JGU

Ants react to social isolation in a similar way as do humans and other social mammals. A study by an Israeli-German research team has revealed alterations to the social and hygienic behavior of ants that had been isolated from their group. The research team was particularly surprised by the fact that immune and stress genes were downregulated in the brains of the isolated ants. "This makes the immune system less efficient, a phenomenon that is also apparent in socially isolating humans - notably at present during the COVID-19 crisis," said Professor Susanne Foitzik, who headed up the study at Johannes Gutenberg University Mainz (JGU). The study on a species of ant native to Germany has recently been published in Molecular Ecology.

Effects of isolation in social insects little studied so far

Humans and other social mammals experience isolation from their group as stressful, having a negative impact on their general well-being and physical health. "Isolated people become lonely, depressed, and anxious, develop addictions more easily, and suffer from a weakened immune system and impaired overall health," added Professor Inon Scharf, lead author of the article and cooperation partner of the Mainz research group at Tel Aviv University in Israel. While the effects of isolation have been extensively studied in social mammals such as humans and mice, less is known about how social insects respond in comparable situations - even though they live in highly evolved social systems. Ants, for instance, live their entire lives as members of the same colony and are dependent on their colony mates. The worker ants relinquish their own reproductive potential and devote themselves to feeding the larvae, cleaning and defending the nest, and searching for food, while the queen does little more than just lay eggs.

The research team looked at the consequences of social isolation in the case of ants of the species Temnothorax nylanderi. These ants inhabit cavities in acorns and sticks on the ground in European forests, forming colonies of a few dozen workers. Young workers engaged in brood care were taken singly from 14 colonies and kept in isolation for varying lengths of time, from one hour to a maximum of 28 days. The study was conducted between January and March 2019 and highlighted three particular aspects in which changes were observed. After the end of their isolation, the workers were less interested in their adult colony mates, but the length of time they spent in brood contact increased; they also spent less time grooming themselves. "This reduction in hygienic behavior may make the ants more susceptible to parasites, but it is also a feature typical of social deprivation in other social organisms," explained Professor Susanne Foitzik.

CAPTION

Drawing of a Temnothorax nylanderi worker ant

CREDIT

ill./©: Inon Scharf, Tel Aviv University

Stress due to isolation adversely affects the immune system

While the study revealed significant changes in the behaviors of the isolated insects, its findings with regard to gene activity were even more striking: Many genes related to immune system function and stress response were downregulated. In other words, these genes were less active. "This finding is consistent with studies on other social animals that demonstrated a weakening of the immune system after isolation," said Professor Inon Scharf.

The discovery by the team of biologists led by Professor Susanne Foitzik is the first of its kind, combining behavioral and genetic analyses on the effects of isolation in social insects. "Our study shows that ants are as affected by isolation as social mammals are and suggests a general link between social well-being, stress tolerance, and immunocompetence in social animals," concluded Foitzik, summarizing the results of the Israeli-German study. Foitzik is also collaborating with her Israeli partner Professor Inon Scharf and with co-author and group leader Dr. Romain Libbrecht of JGU on a new joint project on the fitness benefits and the molecular basis of spatial learning in ants, funded by the German Research Foundation (DFG).

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Related links:

https://www.blogs.uni-mainz.de/fb10-evolutionary-biology/research-groups/group-foitzik/ - Evolution and Behavioral Ecology of Ants group at the JGU Institute of Organismic and Molecular Evolution

Read more:

https://www.uni-mainz.de/presse/aktuell/10918_ENG_HTML.php - press release "Communication and waterproofing: Melting properties determine the biological functions of the cuticular hydrocarbon layer of ants" (26 Feb. 2020) ;

https://www.uni-mainz.de/presse/aktuell/7703_ENG_HTML.php - press release "Arms race between ant societies: Gene activity in defenders depends on invading slavemaking ants" (28 Feb. 2019) ;

https://www.uni-mainz.de/presse/aktuell/5983_ENG_HTML.php - press release "A study of ants provides information on the evolution of social insects" (10 Sept. 2018) ;

https://www.uni-mainz.de/presse/aktuell/5412_ENG_HTML.php - press release "Brood care gene steers the division of labor among ants" (19 June 2018) ;

https://www.uni-mainz.de/presse/aktuell/2007_ENG_HTML.php - press release "Chemical profile of ants adapts rapidly" (14 Aug. 2017)

One of Africa's rarest primates protected by... speedbumps

WILDLIFE CONSERVATION SOCIETY

Research News

ZANZIBAR CITY (April 7, 2021) - A new study revealed that a drastic reduction of deaths of one of Africa's rarest primates, the Zanzibar red colobus (Piliocolobus kirkeii), followed the installation of four speedbumps along a stretch of road where the species frequently crossed.

Zanzibar red colobus are found only in the Zanzibar archipelago and classified as Endangered by the IUCN Red List. Reliant on Unguja Island's forests for their survival, around half of the species population is found in Jozani-Chwaka Bay National Park.

In the study, published in Oryx - The International Journal of Conservation, primatologists from Bangor University, in collaboration with national park managers from Zanzibar and the Wildlife Conservation Society (WCS), assessed mortality from vehicle collisions - a growing threat faced by primates living in increasingly fragmented habitats crisscrossed by roads.

They found that historic data from the road traversing the national park showed that one colobus was killed on average every 2-3 weeks by traffic. After speedbumps were installed, this was reduced to one every six weeks.

While great progress, this mortality rate is still a significant threat to the species - especially given that natural predation tends to target weaker individuals, yet roadkill is indiscriminate, killing reproductively active adults as well as the very young and old.

Bangor primatologist and Director of the Zanzibar Red Colobus Project, Dr. Alexander Georgiev, and senior author of this study, said: "Cars are not selective in the animals they kill. This means that while natural predators may target the very young and old more often, cars are equally likely to kill reproductively active young adults, who would contribute the most to population growth. And this may be a problem."

Harry Olgun, now a PhD student at the University's School of Natural Sciences, led this study as part of his Masters research on the road ecology of the Zanzibar red colobus. Olgun said: "After the road at Jozani was surfaced but before the speedbumps were installed, a colobus was reported to have been killed every two to three weeks, resulting in perhaps about 12-17 percent annual mortality, according to one estimate. The recent data show that speedbumps have made a huge difference for the safety of the colobus. Adding more speedbumps would help reduce the risk further."

Dr. Tim Davenport, Director of Species Conservation & Science in Africa at WCS, who led the first countrywide census of the Zanzibar red colobus a few years ago and is a coauthor of the study, said: "As tourism grows in Zanzibar and habitat continues to shrink, using science to quantify and solve conservation problems has never been so important. Understanding the impact of vehicles on wildlife within a park, and implementing practical solutions is exactly what we as conservationists should be doing."

WCS (Wildlife Conservation Society)

MISSION: WCS saves wildlife and wild places worldwide through science, conservation action, education, and inspiring people to value nature. To achieve our mission, WCS, based at the Bronx Zoo, harnesses the power of its Global Conservation Program in nearly 60 nations and in all the world's oceans and its five wildlife parks in New York City, visited by 4 million people annually. WCS combines its expertise in the field, zoos, and aquarium to achieve its conservation mission. Visit: newsroom.wcs.org Follow: @WCSNewsroom. For more information: 347-840-1242.

Opinion: It took a sea and land journey to prove to scientists they were wrong about physics

Opinion by Don Lincoln 1 day ago

In 2013, a load of precious cargo was put on a barge and transported from the Smith Point Marina on Long Island, down the east coast of the US and up the Mississippi River and its tributaries. When the barge got close to Chicago, the freight was transferred to a flatbed tractor trailer and driven the rest of the way to its destination just west of the Windy City. It was a 50-foot-wide load, so the truck only drove at night.

© Reidar Hahn/Fermilab The g-2 Muon Magnet Ring - first nights move to the staging area at Costco in Bolingbrook

What was this precious cargo? A scientific instrument that researchers hoped would shed new light on the field of physics once it reached its new home in a new lab.


Eight years later, this equipment has done just that. On Wednesday, a scientific measurement, recorded by this apparatus, was publicly released. This may not sound like much, but this single measurement tells scientists that their theory about what is called the standard model of particle physics is incomplete -- and has to be rethought.

As counterintuitive as it may seem, this is not bad news. The purpose of science is to seek truth. With this goal in mind, researchers are constantly returning to their data and checking to see if measurements and theories agree or disagree. While agreement is always satisfying, it's in the disagreement that progress is made. When a theory is shown to predict something other than what a valid measurement has revealed, scientists rethink their theory and adjust it.

The standard model of particle physics, at the center of this news, explains the world of atoms and smaller things, and it was developed in the 1960s and 1970s. It has been universally accepted in the scientific world as being the most accurate subatomic theory devised so far. But that venerable model could well need to be changed because of this new measurement, which gives us reason to believe that the standard model is incomplete.

What the standard model predicts -- and what this new measurement assesses -- are the magnetic properties of an ephemeral subatomic particle called a muon, which is very similar to the familiar electron, but with some differences. Muons are about 200 times heavier than electrons and they decay in a little over a millionth of a second. Otherwise, electrons and muons have a lot in common.

They both, for instance, have electric charge and they spin. A spinning electric charge becomes a magnet. And if you generate a magnetic field and put a spinning charge in it, the charge precesses like a top does, tracing out a circle with its tip while it spins.

Scientists can use accepted laws of physics to predict just how fast the muon should precess. So, over two decades ago, researchers working at the Brookhaven National Laboratory on Long Island, New York, conducted what is called the Muon g-2 (gee minus two) experiment.

These scientists measured how fast the muon actually precesses and the prediction from the standard model and measurement disagreed. When data and theory disagree, one (or both) of them, must be wrong. And if the theory is wrong, that's because scientists overlooked something when they crafted it.

To give a practical example, introductory physics says that a thrown baseball will follow a perfect parabolic arc. However, that prediction ignores real world air resistance and thus the simple prediction and the actual path of the baseball disagree. In order to be accurate, the theory must be expanded to include the effects due to air drag.

The disagreement between measured and predicted precession properties of muons could have meant that our best understanding of the subatomic world is overlooking something. Or it could have meant that the original experiment was flawed in some way. A second and hopefully more precise measurement was needed.

However, the equipment at Brookhaven had been pushed to its limit. A more precise measurement required that another laboratory get involved. Enter Fermilab, America's flagship particle physics laboratory, located just west of Chicago. (Full disclosure: I am a Fermilab scientist but am not involved with the g-2 research effort.)

So, the g-2 experimental equipment -- a ring of magnets in the shape of a hula hoop, 50 feet across and 6 feet high -- took that long trip by boat and truck from Long Island to Fermilab, just outside of Chicago.

Fermilab researchers combined the g-2 measuring device with Fermilab's more powerful muon beams and repeated the measurement. And they just released their first experimental results. Not only do the prediction and new and improved measurement of the magnetic properties of muons still disagree, but the increased precision is even more suggestive that there is something important being overlooked in the standard model theory.

And the researchers aren't done. The recently released measurement is based on only about 6% of the total expected data. The scientists are reporting on this small fraction of the data because they are still recording and validating the rest. When the rest is available, carefully vetted, and published, it will vastly improve the precision of the final measurement. It is likely that the measurement using the entire data set will prove without a doubt that the best theory scientists have for the subatomic world -- one that has been tested and validated for over half a century -- is incomplete and will need recrafting.

Truthfully, this is why I love science so much. It's never complete. It's never absolute. It's always open to new data and new ideas. It is constantly being challenged and tested by people who know it best. And sometimes measurements are made that tell the experts that the theory that they've known for years needs to be revisited. The recently released results are one such measurement.

When you recognize that discovering truth is more important than proving yourself right, you realize that being wrong teaches you something new. And if you accept and embrace that newness, you have a much better chance of actually being right. That's what science is all about.




a person that is standing in the grass: 

The muon g-2 equipment being transported to Fermilab.

The author Don Lincoln

 

New evidence for a '5th force' of nature

Duration: 06:15  

https://wus-streaming-video-msn-com.akamaized.net/78b9e7e1-387f-462e-ad84-e8a5015ff95d/8d4f058b-05b6-4983-9c57-28b43234_2250.mp4

Preliminary results from two experiments suggest something could be wrong with the basic way physicists think the universe works, raising the possibility of a newly discovered fundamental force.

First results from Fermilab's Muon g-2 experiment strengthen evidence of new physics

UMass Amherst researchers contribute to landmark findings

UNIVERSITY OF MASSACHUSETTS AMHERST

Research News

 

IMAGE: DAVID FLAY EXAMINES THE MUON G-2 PLUNGING PROBE INSTALLATION. view more 

CREDIT: FERMILAB/DOE

AMHERST Mass. - The long-awaited first results from the Muon g-2 experiment at the U.S. Department of Energy's Fermi National Accelerator Laboratory show fundamental particles called muons behaving in a way that is not predicted by scientists' best theory, the Standard Model of particle physics. This landmark result, made with unprecedented precision and to which UMass Amherst's David Kawall's research group made key contributions, confirms a discrepancy that has been gnawing at researchers for decades.

"Today is an extraordinary day, long awaited not only by us but by the whole international physics community," said Graziano Venanzoni, co-spokesperson of the Muon g-2 experiment and physicist at the Italian National Institute for Nuclear Physics. "A large amount of credit goes to our young researchers who, with their talent, ideas and enthusiasm, have allowed us to achieve this incredible result."

"It's fantastically interesting to work on," says Kawall, a professor in UMass's physics department. "Everything matters. Every little detail matters, and all future theories of physics will have to be compatible with this result."

A muon is about 200 times as massive as its cousin, the electron. Muons occur naturally when cosmic rays strike Earth's atmosphere, and particle accelerators at Fermilab can produce them in large numbers. Like electrons, muons act as if they have a tiny internal magnet. In a strong magnetic field, the direction of the muon's magnet precesses, or wobbles, are much like the axis of a spinning top or gyroscope. The strength of the internal magnet determines the rate that the muon precesses in an external magnetic field and is described by a number that physicists call the g-factor. This number can be calculated with ultra-high precision.

Kawall's group, which included postdocs David Flay and Jimin George, graduate student David Kessler, and undergrad Alysea Kim, worked on measuring the strength of the magnetic field through which the muons passed, as well as preparing the magnet itself, a feat requiring almost unimaginable precision. "One of the innovations we were responsible for," says Kawall, "was developing a system involving 8,000 sheets of laser-cut iron foil to make the magnetic field as homogenous as possible. With our system, we were able to achieve results nearly three times better than the previous experiment." The team also spent years developing special calibration probes of incredible fidelity, accurate down to 15 parts per billion.

As the muons circulate in the Muon g-2 magnet, they also interact with a quantum foam of subatomic particles popping in and out of existence. Interactions with these short-lived particles affect the value of the g-factor, causing the muons' precession to speed up or slow down very slightly. The Standard Model predicts this so-called anomalous magnetic moment extremely precisely. But if the quantum foam contains additional forces or particles not accounted for by the Standard Model, that would tweak the muon g-factor further.

"This quantity we measure reflects the interactions of the muon with everything else in the universe. But when the theorists calculate the same quantity, using all of the known forces and particles in the Standard Model, we don't get the same answer," said Renee Fatemi, a physicist at the University of Kentucky and the simulations manager for the Muon g-2 experiment. "This is strong evidence that the muon is sensitive to something that is not in our best theory."

With more than 200 scientists from 35 institutions in seven countries, the Muon g-2 collaboration has now finished analyzing the motion of more than 8 billion muons from that first run.

"So far we have analyzed less than 6% of the data that the experiment will eventually collect. Although these first results are telling us that there is an intriguing difference with the Standard Model, we will learn much more in the next couple of years," says Fermilab scientist Chris Polly.

"Pinning down the subtle behavior of muons is a remarkable achievement that will guide the search for physics beyond the Standard Model for years to come," said Fermilab Deputy Director of Research Joe Lykken. "This is an exciting time for particle physics research, and Fermilab is at the forefront."

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More images of the Muon g-2 experiment are available here.
A fact sheet is available here.

https://www.umass.edu/newsoffice/article/first-results-fermilab%E2%80%99s-muon-g-2 

 

Race and poverty appear to guide heart muscle DNA methylation in heart-failure patients

Differences in DNA methylation correlated with differences in heart-failure outcomes, as measured by two-year mortality.

UNIVERSITY OF ALABAMA AT BIRMINGHAM

Research News

 

IMAGE: ADAM WENDE view more 

CREDIT: UAB

BIRMINGHAM, Ala. - Race associates with the risk of death from end-stage heart failure. So, identifying the molecular determinants of that risk may help the pursuit of the novel diagnosis and prognosis of heart failure, and its therapy.

A University of Alabama at Birmingham study of end-stage heart-failure patients has found that cytosine-p-guanine, or CpG, methylation of the DNA in the heart has a bimodal distribution among the patients, and that race -- African American versus Caucasian -- was the sole variable in patient records that explained the difference. A subsequent look at the census tracts where the patients lived showed that the African American subjects lived in neighborhoods with more racial diversity and poverty, suggesting that the underlying variable may be a socioeconomic difference.

Methylation of DNA is a form of epigenetics, an indirect method of gene regulation that can change with gene-environment interaction. Previously the Wende laboratory has shown that these DNA modifications differentiate ischemic and non-ischemic heart failure.

The current UAB study included a pilot cohort of 11 heart-failure patients, followed by a testing cohort of 31 heart-failure patients, all of them male. The heart muscle tissue for the study was obtained when patients underwent surgery to install a left ventricular assist device, or LVAD -- a small mechanical pump carried outside the body that helps a weakened heart pump blood. During the surgery, a piece of the left ventricle is excised; it is otherwise discarded but could be used for this study.

Heretofore, epigenetics has been an underexplored source of heterogeneity among patients with end-stage heart failure. The UAB researchers found differential promoter hyper-methylation of genes involved in fatty acid metabolism among African American heart muscle samples, relative to Caucasian samples, and also higher expression of lipogenesis genes. Such metabolic perturbations are a pathological hallmark of end-stage heart failure, as the heart gets more of its energy from glycolysis -- that is from glucose sugar -- as it fails.

This finding generated two hypotheses, says Adam R. Wende, Ph.D., the associate professor in the UAB Department of Pathology who led the study: 1) that the epigenetic remodeling of cardiac gene regulation determines the therapeutic potential of LVADs, and 2) that epigenetic reprogramming of cardiac gene regulation constitutes a mechanism that may influence responsiveness to LVAD-induced cardiac unloading, meaning possible improvement of the heart as the pump takes over part of the work.

In contrast to the hyper-methylated promoters, the genes that had differentially hypo-methylated promoters, or lower levels of methylation, in African American hearts disproportionately represented inflammatory signaling cascades.

Additionally, the UAB researchers did a retrospective analysis of deaths from any cause in the 31 testing cohort patients two years after heart pump implantation. African Americans had a significantly higher rate of death, eight of 15 patients, versus Caucasians, two of 14.

The need for better treatment of heart failure is great. Only half of heart-failure patients respond to medical management, and African Americans experience worse clinical outcomes than any United States race or ethnicity.

"African Americans with heart failure are hospitalized at a rate 2.5-times higher than other races or ethnicities," Wende said. "Furthermore, despite a threefold higher mortality from heart-failure complications, the prevalence of heart failure among African Americans continues to increase."

"It is estimated that 3.6 percent of this community will live with heart failure by 2030, exceeding the predicted prevalence of any other race or ethnicity in America," Wende said. "Therefore, it is paramount to identify and address the issues that underly these disturbing racial differences in heart-failure morbidity and mortality."

The UAB researchers noted the limitation that this was a single-center study; but Wende said, "Nevertheless, we provide preliminary evidence that socioeconomic factors are likely associated with racial differences in cardiac DNA methylation among men with end-stage heart failure."

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Co-authors with Wende and first author Mark Pepin, M.D., Ph.D., in the study, "Racial and socioeconomic disparity associates with differences in cardiac DNA methylation among men with end-stage heart failure," published in the American Journal of Physiology: Heart and Circulatory Physiology, are Chae-Myeong Ha, Luke A. Potter and Sayan Bakshi, Division of Molecular and Cellular Pathology, UAB Department of Pathology; Joseph P. Barchue, Ayman Haj Asaad, Steven M. Pogwizd and Salpy V. Pamboukian, Division of Cardiovascular Disease, UAB Department of Medicine; Bertha A. Hidalgo, Department of Epidemiology, UAB School of Public Health; and Selwyn M. Vickers, Office of the Dean and Senior Vice President for Medicine, UAB School of Medicine.

Support came from National Institutes of Health grants MD008620 Center for Healthy African American Men through Partnerships, or CHAAMPS, TR001417, HL133011, HL137240 and HL154571.

Pepin, now at the Institute for Experimental Cardiology, Heidelberg University Hospital, Germany, did his research as a graduate student in UAB's Medical Scientist Training Program, an integrated M.D.-Ph.D. program.

A discovery that "literally changes the textbook"

MSU's expertise in fish biology, genetics helping researchers rewrite evolutionary history and shape future health studies

MICHIGAN STATE UNIVERSITY

Research News

 

IMAGE: BEHOLD, THE GAR'S BRAIN. IN THIS MICROSCOPE IMAGE, THE BRAIN'S LEFT HEMISPHERE FLUORESCES GREEN AND THE RIGHT GLOWS MAGENTA. YET, AT THE BOTTOM OF THE IMAGE, NERVES OF BOTH COLORS... view more 

CREDIT: REPRINTED WITH PERMISSION FROM R.J. VIGOUROUX ET AL. SCIENCE 372:EABE7790 (2021)

The network of nerves connecting our eyes to our brains is sophisticated and researchers have now shown that it evolved much earlier than previously thought, thanks to an unexpected source: the gar fish.

Michigan State University's Ingo Braasch has helped an international research team show that this connection scheme was already present in ancient fish at least 450 million years ago. That makes it about 100 million years older than previously believed.

"It's the first time for me that one of our publications literally changes the textbook that I am teaching with," said Braasch, as assistant professor in the Department of Integrative Biology in the College of Natural Science.

This work, published in the journal Science on April 8, also means that this type of eye-brain connection predates animals living on land. The existing theory had been that this connection first evolved in terrestrial creatures and, from there, carried on into humans where scientists believe it helps with our depth perception and 3D vision.

And this work, which was led by researchers at France's Inserm public research organization, does more than reshape our understanding of the past. It also has implications for future health research.

Studying animal models is an invaluable way for researchers to learn about health and disease, but drawing connections to human conditions from these models can be challenging.

Zebrafish are a popular model animal, for example, but their eye-brain wiring is very distinct from a human's. In fact, that helps explain why scientists thought the human connection first evolved in four-limbed terrestrial creatures, or tetrapods.

"Modern fish, they don't have this type of eye-brain connection," Braasch said. "That's one of the reasons that people thought it was a new thing in tetrapods."

Braasch is one of the world's leading experts in a different type of fish known as gar. Gar have evolved more slowly than zebrafish, meaning gar are more similar to the last common ancestor shared by fish and humans. These similarities could make gar a powerful animal model for health studies, which is why Braasch and his team are working to better understand gar biology and genetics.

That, in turn, is why Inserm's researchers sought out Braasch for this study.

"Without his help, this project wouldn't have been possible," said Alain Chédotal, director of research at Inserm and a group leader of the Vision Institute in Paris. "We did not have access to spotted gar, a fish that does not exist in Europe and occupies a key position in the tree of life."

To do the study, Chédotal and his colleague, Filippo Del Bene, used a groundbreaking technique to see the nerves connecting eyes to brains in several different fish species. This included the well-studied zebrafish, but also rarer specimens such as Braasch's gar and Australian lungfish provided by a collaborator at the University of Queensland.

In a zebrafish, each eye has one nerve connecting it to the opposite side of the fish's brain. That is, one nerve connects the left eye to the brain's right hemisphere and another nerve connects its right eye to the left side of its brain.

The other, more "ancient" fish do things differently. They have what's called ipsilateral or bilateral visual projections. Here, each eye has two nerve connections, one going to either side of the brain, which is also what humans have.

Armed with an understanding of genetics and evolution, the team could look back in time to estimate when these bilateral projections first appeared. Looking forward, the team is excited to build on this work to better understand and explore the biology of visual systems.

"What we found in this study was just the tip of the iceberg," Chédotal said. "It was highly motivating to see Ingo's enthusiastic reaction and warm support when we presented him the first results. We can't wait to continue the project with him."

Both Braasch and Chédotal noted how powerful this study was thanks to a robust collaboration that allowed the team to examine so many different animals, which Braasch said is a growing trend in the field.

The study also reminded Braasch of another trend.

"We're finding more and more that many things that we thought evolved relatively late are actually very old," Braasch said, which actually makes him feel a little more connected to nature. "I learn something about myself when looking at these weird fish and understanding how old parts of our own bodies are. I'm excited to tell the story of eye evolution with a new twist this semester in our Comparative Anatomy class."

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(Note for media: Please include a link to the original paper in online coverage: https://doi.org/10.1126/science.abe7790)

Earth's crust mineralogy drives hotspots for intraterrestrial life

FRONTIERS

Research News

 

IMAGE: DEMMO FIELD TEAM FROM LEFT TO RIGHT: LILY MOMPER, BRITTANY KRUGER, AND CAITLIN CASAR SAMPLING FRACTURE FLUIDS FROM A DEMMO BOREHOLE INSTALLATION view more 

CREDIT: ©MATT KAPUST

Below the verdant surface and organic rich soil, life extends kilometers into Earth's deep rocky crust. The continental deep subsurface is likely one of the largest reservoirs of bacteria and archaea on Earth, many forming biofilms - like a microbial coating of the rock surface. This microbial population survives without light or oxygen and with minimal organic carbon sources, and can get energy by eating or respiring minerals. Distributed throughout the deep subsurface, these biofilms could represent 20-80% of the total bacterial and archaeal biomass in the continental subsurface according to the most recent estimate. But are these microbial populations spread evenly on rock surfaces, or do they prefer to colonize specific minerals in the rocks?

To answer this question, researchers from Northwestern University in Evanston, Illinois, led a study to analyze the growth and distribution of microbial communities in deep continental subsurface settings. This work shows that the host rock mineral composition drives biofilm distribution, producing "hotspots" of microbial life. The study was published in Frontiers in Microbiology.

Hotspots of microbial life

To realize this study, the researchers went 1.5 kilometers below the surface in the Deep Mine Microbial Observatory (DeMMO), housed within a former gold mine now known as the Sanford Underground Research Facility (SURF), located in Lead, South Dakota. There, below-ground, the researchers cultivated biofilms on native rocks rich in iron and sulfur-bearing minerals. After six months, the researchers analyzed the microbial composition and physical characteristics of newly grown biofilms, as well as its distributions using microscopy, spectroscopy and spatial modelling approaches.

The spatial analyses conducted by the researchers revealed hotspots where the biofilm was denser. These hotspots correlate with iron-rich mineral grains in the rocks, highlighting some mineral preferences for biofilm colonization. "Our results demonstrate the strong spatial dependence of biofilm colonization on minerals in rock surfaces. We think that this spatial dependence is due to microbes getting their energy from the minerals they colonize." explains Caitlin Casar, first author of the study.

Future research

Altogether, these results demonstrate that host rock mineralogy is a key driver of biofilm distribution, which could help improve estimates of the microbial distribution of the Earth's deep continental subsurface. But leading intraterrestrial studies could also inform other topics. "Our findings could inform the contribution of biofilms to global nutrient cycles, and also have astrobiological implications as these findings provide insight into biomass distributions in a Mars analog system" says Caitlin Casar.

Indeed, extraterrestrial life could exist in similar subsurface environments where the microorganisms are protected from both radiation and extreme temperatures. Mars, for example, has an iron and sulfur-rich composition similar to DeMMO's rock formations, which we now know are capable of driving the formation of microbial hotspots below-ground.

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