Thursday, February 22, 2024

 

How discrimination, class, and gender intersect to affect Black Americans’ well-being


Peer-Reviewed Publication

UNIVERSITY OF ILLINOIS COLLEGE OF AGRICULTURAL, CONSUMER AND ENVIRONMENTAL SCIENCES

TeKisha Rice and Brian Ogolsky 

IMAGE: 

TEKISHA RICE AND BRIAN OGOLSKY.

view more 

CREDIT: UNIVERSITY OF ILLINOIS.




URBANA, Ill. – Black Americans experience racial discrimination as a chronic stressor that influences their quality of life. But it exists in conjunction with other social factors that may modify the impact in various ways. A new study from the University of Illinois Urbana-Champaign explores how discrimination, gender, and social class affect individual well-being and relationship quality for Black Americans.

“It’s well documented that discrimination negatively impacts individual quality of life, but research on how it affects relationships is mixed. Some studies find it has a negative effect, others that it has no effect, and some even find a positive effect, such as more partner support. We were interested in how intersecting dimensions of sexism and classism could provide more insights,” said lead author TeKisha Rice, now an assistant professor at Virginia Tech. Rice conducted the research as a doctoral student at the U. of I. Brian Ogolsky, professor in the Department of Human Development and Family Studies, part of the College of Agricultural, Consumer and Environmental Sciences (ACES) at U. of I., is a co-author on the paper, which is published in the Journal of Family Psychology.

Rice and Ogolsky found that racial discrimination and financial strain were associated with lower levels of psychological well-being. However, the anticipated interaction between factors varied by gender.

“We found that among women who had higher levels of financial strain, racial discrimination predicted lower levels of quality of life, but this association did not show up for men in the study,” Rice said. “There is a gender dynamic in the way discrimination affects psychological and relational well-being. This aligns with other research indicating that Black women, in particular, may take on more of the emotional labor of their relationships.”

The researchers used data from the Survey of Midlife in the United States (MIDUS), a large-scale, longitudinal study that measures health and psychological well-being in individuals across the U.S. They included respondents who identified as Black or African American, and who were married or cohabitating. Participants ranged from 27 to 83 years old, with an average age of 53, and all were in heterosexual relationships.

The findings also speak to the potential resilience of Black individuals in the face of discrimination, the researchers said.

“One of the theories we use to understand the results is the Mundane Extreme Environmental Stress (MEES) model, which states that racial discrimination is mundane because it is common, but also extreme because of the negative impact that it can have on people's lives,” Rice noted. “As people get older, the way they respond to discrimination may be different. Perhaps they have gotten used to ignoring it, or they have effective coping mechanisms in place already.”

This can help explain the non-significant findings for Black men in this dataset, which had a large proportion of middle-aged respondents.

In addition, there are different types and levels of discrimination, Ogolsky added. “A single, major discriminatory event could influence well-being differently than low-level chronic discrimination. We need to think about these events with a fine-toothed comb, looking at both frequency and salience of discrimination.”  

As the MEES theory indicates, Black Americans may come to expect discrimination as a part of life. But the chronic stress of financial strain might be felt in material ways that impact relationship experiences.

“For example, a couple may have to talk about bills and figure out how to ration expenses. It’s not that financial strain is more negative than discrimination, but it may be felt more directly on a day-to-day basis,” Ogolsky stated.

Future studies should explore the gender differences in how Black Americans are navigating or experiencing racial discrimination. For practitioners who work with couples, it’s important to be attentive to how each partner might be responding differently to discrimination and the ways it can generate potential distress, the researchers concluded. 

The paper, “Discrimination, Gender, and Class: An Intersectional Investigation of Black Americans’ Personal and Relational Well-Being,” is published in the Journal of Family Psychology [DOI: 10.1037/fam0001173].  

This research was completed as a part of the first author’s dissertation, funded by the National Science Foundation Graduate Research Fellowship Program (Grant No. DGE -1144245).

Study finds guided parent-child discussions are effective at addressing subtle racism


When parents discuss racism with their children, negative biases toward Black people are significantly reduced in both parent and child


Peer-Reviewed Publication

NORTHWESTERN UNIVERSITY





Study finds guided parent-child discussions are effective at addressing subtle racism
When parents discuss racism with their children, negative biases toward Black people are significantly reduced in both parent and child

EVANSTON, Ill. --- Experts have long pointed out the need for white parents to have conversations that directly address racism with their children to reduce racial bias. But many parents fail to have these crucial discussions.

Psychology researchers at Northwestern University have published the first study to demonstrate the immediate effectiveness of a guided discussion task to promote parent-child conversations about racial bias in white U.S. families.

The researchers created a discussion guide that would support parents to have “color conscious” conversations with their children that would explicitly acknowledge the existence and history of racism, and its continued presence.  

According to the study, parents who engaged in color conscious discussions with their 8- to 12-year-old child showed a significant decrease in anti-Black bias, and so did their children. However, even in conversations in which parents made comments that downplayed the importance of race or deflected blame away from white perpetrators of racism, the researchers saw reductions in bias.

“A lot of parents worry that talking to their kids about racism could increase their children’s biases, and they also feel like they don’t know how to do it,” said corresponding author Sylvia Perry. “Our key finding, however, was that when parents used color conscious language while discussing interpersonal racism, it was associated with a significant decrease in their child’s negative implicit biases toward Black people.”

Perry is an associate professor of psychology and principal investigator for the Social Cognition and Intergroup Processes Laboratory at Weinberg College of Arts and Sciences, and a faculty fellow at the Institute for Policy Research at Northwestern.

Perry said two questions prompted the research. First, if white parents and their children participated in a guided racism discussion task, would they have color conscious conversations? Second, if white parents and their children did have color conscious conversations, would children show a measurable decrease in their anti-Black biases following the conversation? 

Guided discussion as a tool
The researchers recruited 84 self-described white parent-child pairs to participate in the study.

Parents were asked to start a conversation with their child after watching videos that depicted interactions between a white child and a Black child. The series of scenes featured overt prejudice, subtle prejudice or neutral interactions between the children. Parents were provided with suggested discussion prompts such as, “Why did the white child do what they did?” and “How do you think the Black child felt after it happened?” — intended to encourage parents and children to articulate whether racial prejudice had occurred and to consider the negative impact of racism on Black children.

Parents and children individually completed implicit association tests to measure their degree of anti-Black bias before and after the guided discussion task.

Study findings
The researchers were surprised to find that even when parents used colorblind language in discussing the videos with their children, for example, saying, “Black and white people are all the same,” their children still showed reductions in their biases; the effects were just smaller.

Perry noted, however, that the observed decreases occurred while parents and children were participating in a guided racism discussion task designed to mitigate prejudice. While some families used colorblind language at some point during their discussion, most of those families also used color conscious language. Overall, 92% of parents and 95% of children, used color conscious language during the discussion.

The children's anti-Black biases showed a significant decline after completion of the discussion task. Children showed a moderate preference for white over Black individuals, with an implicit bias score of 0.41 before the task. After the discussion task, the score was reduced to 0.16, bringing them closer to little or no bias. Parents’ anti-Black biases also decreased significantly, from 0.53 to 0.34, after the discussion task.

Addressing subtle prejudice
Because subtle forms of prejudice have negative effects on the mental and physical health of Black individuals the researchers said it is a lost opportunity for parents to engage only in conversations about blatant racism.

“We specifically found beneficial effects of parents’ language on their children’s anti-Black biases when they were discussing subtle instances of racism,” said Deborah Wu, an assistant professor of psychology at Stonehill College, and a co-author of the study. “Our results suggest that having these specific color conscious conversations, as well as refraining from explaining away racism is especially helpful when discussing subtler forms of racism. This is especially important, as subtle forms of racism are far more common than overt racism and more likely to be dismissed by white individuals.”

The researchers found that parents who made clear to their children that the white child’s racial prejudice was influencing the white child’s attitudes or behaviors toward the Black child, such as feeling uncomfortable around Black children, had children who were most likely to show a reduction in negative biases towards Black people.

Two-way influence
The researchers also looked at the influence children had on their parent’s attitudes. They found that when children made external attributions, such as saying a child might be prejudiced because they learned it from their parents, their parents showed bigger reductions in their anti-Black biases.

“Another key takeaway of this study is that it demonstrates the utility of family-level racism interventions to reduce racial bias in both adults and children,” said Jamie L. Abaied, an associate professor of psychological science at the University of Vermont and a co-author of the study. “The experience of viewing and discussing vignettes depicting racism alongside one’s child may be particularly eye-opening for white parents, and it may help them grapple with the idea that if they do not take steps to prevent it, their own child could potentially engage in racist behaviors like the white children in the videos.”

"White Parents' Racial Socialization During a Guided Discussion Predicts Declines in White Children's Pro-White Biases" will be published by the journal Developmental Psychology on Feb. 22. Access it online here.

 

Snakes do it faster, better: How a group of scaly, legless lizards hit the evolutionary jackpot


Peer-Reviewed Publication

UNIVERSITY OF MICHIGAN





More than 100 million years ago, the ancestors of the first snakes were small lizards that lived alongside other small, nondescript lizards in the shadow of the dinosaurs.

 

Then, in a burst of innovation in form and function, the ancestors of snakes evolved legless bodies that could slither across the ground, highly sophisticated chemical detection systems to find and track prey, and flexible skulls that enabled them to swallow large animals.

 

Those changes set the stage for the spectacular diversification of snakes over the past 66 million years, allowing them to quickly exploit new opportunities that emerged after an asteroid impact wiped out roughly three-quarters of the planet's plant and animal species.

 

But what triggered the evolutionary explosion of snake diversity—a phenomenon known as adaptive radiation—that led to nearly 4,000 living species and made snakes one of evolution's biggest success stories?

 

A large new genetic and dietary study of snakes, from an international team led by University of Michigan biologists, suggests that speed is the answer. Snakes evolved up to three times faster than lizards, with massive shifts in traits associated with feeding, locomotion and sensory processing, according to the study scheduled for online publication Feb. 22 in the journal Science.

 

"Fundamentally, this study is about what makes an evolutionary winner. We found that snakes have been evolving faster than lizards in some important ways, and this speed of evolution has let them take advantage of new opportunities that other lizards could not," said University of Michigan evolutionary biologist Daniel Rabosky, senior author of the upcoming Science paper.

 

"Snakes evolved faster and—dare we say it—better than some other groups. They are versatile and flexible and able to specialize on prey that other groups cannot use," said Rabosky, a curator at the U-M Museum of Zoology and a professor in the Department of Ecology and Evolutionary Biology.

 

For the study, researchers generated the largest, most comprehensive evolutionary tree of snakes and lizards by sequencing partial genomes for nearly 1,000 species. In addition, they compiled a huge dataset on lizard and snake diets, examining records of stomach contents from tens of thousands of preserved museum specimens.

 

They fed this mountain of data into sophisticated mathematical and statistical models, backed by massive amounts of computer power, to analyze the history of snake and lizard evolution through geological time and to study how various traits, such as limblessness, evolved.

 

This multipronged approach revealed that while other reptiles have evolved many snakelike traits—25 different groups of lizards also lost their limbs, for instance—only snakes experienced this level of explosive diversification.

 

Take Australia's legless gecko, for example.

 

Like snakes, this lizard lost its legs and evolved a flexible skull. Yet the creature has barely diversified over millions of years. No evolutionary explosion—just a couple of species scraping out a living in the Australian outback.

 

So, it seems there is something special about snakes that enabled them to hit the evolutionary jackpot. Maybe something in their genes that allowed them to be evolutionarily flexible while other groups of organisms are much more constrained.

 

"A standout aspect of snakes is how ecologically diverse they are: burrowing
underground, living in freshwater, the ocean and almost every conceivable habitat on land," said Alexander Pyron, study co-author and an associate professor of biology at George Washington University. "While some lizards do some of these things—and there are many more lizards than snakes—there  are many more snakes in most of these habitats in most places."

 

The ultimate causes, or triggers, of adaptive radiations is one of the big mysteries in biology. In the case of snakes, it's likely there were multiple contributing factors, and it may never be possible to tease them apart.

 

The authors of the upcoming Science study refer to this once-in-evolutionary-history event as a macroevolutionary singularity with "unknown and perhaps unknowable" causes.

 

A macroevolutionary singularity can be viewed as a sudden shift into a higher evolutionary gear, and biologists suspect these outbursts have happened repeatedly throughout the history of life on Earth. The sudden emergence and subsequent dominance of flowering plants is another example.

 

In the case of snakes, the singularity started with the nearly simultaneous (from an evolutionary perspective) acquisition of elongated legless bodies, advanced chemical detection systems and flexible skulls.

 

Those crucial changes allowed snakes, as a group, to pursue a much broader array of prey types, while simultaneously enabling individual species to evolve extreme dietary specialization.

 

Today, there are cobras that strike with lethal venom, giant pythons that constrict their prey, shovel-snouted burrowers that hunt desert scorpions, slender tree snakes called  "goo-eaters" that prey on snails and frog eggs high above the ground, paddle-tailed sea snakes that probe reef crevices for fish eggs and eels, and many more.

 

"One of our key results is that snakes underwent a profound shift in feeding ecology that completely separates them from other reptiles," Rabosky said. "If there is an animal that can be eaten, it's likely that some snake, somewhere, has evolved the ability to eat it."

 

For the study, the researchers got an inside look at snake dietary preferences by reviewing field observations and stomach-content records for more than 60,000 snake and lizard specimens, mostly from natural history museums. The contributing museums included the University of Michigan Museum of Zoology, home to the world's largest research collection of snake specimens.

 

"Museum specimens give us this incredible window into how organisms make a living in nature. For secretive animals like snakes, it's almost impossible to get this kind of data any other way because it's hard to observe a lot of their behavior directly," said study co-lead author Pascal Title of Stony Brook University, who completed his doctorate at U-M in 2018.

 

The study's 20 authors are from universities and museums in the United States, the United Kingdom, Australia, Brazil and Finland.

 

"What I love about this study is how it integrates hard-earned field and museum data with new genomic and analytical methods to show a basic biological truth: Snakes are exceptional and frankly quite cool," said co-lead author Sonal Singhal of California State University, Dominguez Hills, who started work on the project as a U-M postdoctoral scholar.

 

The study was supported by several funding agencies, including multiple grants from the U.S. National Science Foundation. More information, including a copy of the study, is available to registered reporters at https://www.eurekalert.org/press/scipak.

 

Study: The macroevolutionary singularity of snakes (DOI: 10.1126/science.adh2449) (available when embargo lifts).

Photos

 

Disclaimer: AAAS

Side effects of wide scale forestation could reduce carbon removal benefits by up to a third


The side effects of large-scale forestation initiatives could reduce the CO2 removal benefits by up to a third, a pioneering study has found.


Peer-Reviewed Publication

UNIVERSITY OF SHEFFIELD



The side effects of large-scale forestation initiatives could reduce the CO2 removal benefits by up to a third

Researchers at the University of Sheffield used computer models, which simulate the land, ocean and atmosphere, to investigate the impact of forestation under future climate scenarios

While forestation increases atmospheric CO2 removal, it also changes atmospheric composition and darkens the land surface, reducing its potential to tackle climate change

Combining forestation with other climate mitigation strategies is vital for more effective long-term climate action

The side effects of large-scale forestation initiatives could reduce the CO2 removal benefits by up to a third, a pioneering study has found.


The research, led by scientists at the University of Sheffield and published today (Thursday 22 February 2024) in the journal Science, provides a new insight into the broader impacts of forestation on the Earth's climate, indicating that its positive impact is potentially smaller than previously thought. 

 

Carbon removal strategies, such as forestation, alongside greenhouse gas emissions reduction efforts, have been recognised by the IPCC as essential measures to mitigate the risk of dangerous future climate change. 

 

By simulating global forest expansion with advanced computer modelling techniques, academics from the University of Sheffield, in collaboration with the Universities of Leeds and Cambridge, and NCAR and WWF, found that while forestation increases absorption of carbon dioxide from the atmosphere, other complex Earth System responses could together partially offset these benefits by up to a third.

 

Dr James Weber, from the University of Sheffield’s School of Biosciences and lead author of the study, said: “The public are bombarded with messages about climate change, and the suggestion that you can plant trees to offset your carbon emissions is widespread. Many businesses now offer to plant a tree with a purchase, and some countries plan to expand, conserve, and restore forests. 

 

“Trees can help tackle climate change, but we need to be careful about relying on them. We need to evaluate forestation, and other climate change mitigation strategies, in detail. This will help identify limitations and unintended consequences so these can be minimised where possible.”

 

The study, which simulated wide scale forestation under two future scenarios—one with minimal efforts to tackle climate change and another with extensive mitigation measures alongside forestation—found that forestation leads to increased CO2 removal. However, it also reduces the reflectivity of the land surface (as trees are darker than grassland) and changes the atmospheric concentrations of other greenhouse gases (methane and ozone) and tiny particles called aerosols. Altogether, these indirect effects partially offset the CO2 reduction benefits, by up to 30 per cent.

 

The study also found that when forestation is implemented alongside other strategies to tackle climate change, such as reducing fossil fuel emissions, the negative impacts of these indirect effects are lower. This highlights the importance of combining forestation efforts with complementary climate change mitigation strategies for more effective long-term climate action.

 

Dr Maria Val Martin, University of Sheffield UKRI Future Leader Fellow and senior author of the study, said: “Drastic CO2 emission reductions along with large-scale removal of atmospheric CO2 are vital to combat climate change effectively. Our study provides a comprehensive analysis of the indirect climate impacts of forestation, revealing that they partially counter the climate benefits achieved through carbon sequestration. Understanding these indirect side effects is essential for developing effective solutions to achieving net-zero emissions.”

 

Dr. Stephanie Roe, WWF Global Climate and Energy Lead Scientist, IPCC AR6 Report Lead Author, and co-author of the study said: “We know that forests are critically important for biodiversity, water, ecosystem services, and the climate. What this research shows is that the effectiveness of reforestation for climate mitigation declines significantly in higher latitudes and unless paired with deep emission reductions which reduces air pollution. It underscores the importance of properly planning reforestation efforts and adequately accounting for biophysical and future climate impacts in different latitudes and regions. Importantly, the study finds that preventing deforestation, when compared to reforestation efforts, is a far more efficient way to mitigate climate change.”

 

Dr Daniel Grosvenor, from the University of Leeds and the Met Office, and co-author of the study said: “What's interesting about this study is that it examines the side effects of forestation that occur via changes in atmospheric chemistry, aerosol particles and surface reflectivity. It shows that the cooling impact of carbon dioxide removal from an extensive, but feasible, global forest expansion could be considerably reduced due to those side effects. This would make it harder than expected to mitigate climate change and to reach the Paris agreement target.”

 

Professor David Edwards, Head of Tropical Ecology and Conservation Group at the University of Cambridge, and not involved in the study, said:  “Global restoration targets are massive – 350 million hectares by 2030 under the Bonn Challenge alone. This study makes a major advance in revealing that the combined impacts of albedo and atmospheric chemistry from forestation offset some of the perceived climate-change-mitigation benefits generated via carbon sequestration. Critically, the study shows that not all forestation is equal, with more favourable potential in the tropics due to aerosol scattering that can offset warming caused by reduced albedo, whereas forestation at higher latitudes may well result in net global warming.”

 

Professor Dominick Spracklen, Professor of Biosphere-Atmosphere Interactions at the University of Leeds, and not involved in the study, said: "This study highlights the amazingly complex role of forests in our climate system. Through calculating how forests alter atmospheric composition, this study provides one of the most comprehensive assessments of the climate impacts of large-scale forestation."

 

ENDS

Media contact: Alice Fletcher, Media and PR Assistant, alice.fletcher@sheffield.ac.uk 

 

The University of Sheffield

The University of Sheffield is a leading Russell Group university, with a world-class reputation. Over 30,000 students from 150 countries study at Sheffield. In a truly global community, they learn alongside over 1,500 of the world’s leading academics.

 

Sheffield’s world-shaping research feeds into its excellent education. Students learn at the leading edge of discovery from researchers who are tackling today’s biggest global challenges. 

Driven by outstanding people, staff and students share a commitment to changing the world for the better, through the power and application of ideas and knowledge.

From the first documented use of penicillin as a therapy in 1930, to building Europe’s largest research-led manufacturing cluster, Sheffield’s inventive spirit and top quality research environment sets it apart. 

 

Current research partners include Boeing, Rolls-Royce, Unilever, AstraZeneca, GlaxoSmithKline, Siemens and Airbus, as well as many government agencies and charitable foundations. 

Sheffield’s Students’ Union has won the Whatuni Student Choice Award for Best Students’ Union for six consecutive years. Students can choose from 350 societies and clubs, or join over 2,000 volunteers. 

 

Over 300,000 Sheffield alumni from 205 different countries make a significant influence across the world, with six Nobel Prize winners included amongst former staff and students.

To find out more, visit: www.sheffield.ac.uk

 

Entrepreneurs’ stock losses bruise their businesses


Company growth stalls when an owner’s personal portfolio takes a hit


Peer-Reviewed Publication

UNIVERSITY OF TEXAS AT AUSTIN




When a recession takes a bite out of an entrepreneur’s personal stock portfolio, does that person’s business suffer more than those of older and larger competitors? 

New research by Marius Ring, assistant professor of finance at Texas McCombs, finds a link between the wealth of small-business owners and the health of their companies during economic downturns. When their stock portfolios lose value, their businesses suffer ripple effects: less financing and curtailed hiring. 

“Entrepreneurial wealth follows the ups and downs of economic cycles,” Ring says. “I show that for entrepreneurs whose stock portfolios take a hit, their businesses are adversely affected to a greater extent than established businesses.”

Such business constrictions are concentrated among younger companies, he noted, because older companies have more financial options. 

Ring studied stock portfolios of entrepreneurs during the 2008-2009 financial crisis in Norway, where detailed income and investing data are available. He merged the data with information from education and employment registers to trace the crash’s impacts on investors, the businesses they own, and their employees.

He found that owners’ stock shortfalls hurt businesses in multiple ways, with fledgling companies faring worse.

Hiring Hiatuses. A stock loss of 10% reduced employment growth by an average 5 percentage points from 2007 to 2010. In younger companies, job levels still had not recovered five years after the crisis began.

Shrinking employment resulted not from firings, but from less hiring. Says Ring, “Investing in new employees is likely not a top priority in a recession.” 

Investment Lessened. A 10% drop in the owner’s wealth led to cutbacks in capital available for business growth. 

  • It reduced injections of outside equity 22%.
  • For younger companies, it meant an 84% decline in the two-year rate of investment in plants and property.

Why are younger businesses more sensitive to their owners’ investment setbacks? The answer, says Ring, is that “more mature firms seem to be able to substitute other sources of financing, such as banks.”

Mature companies, he found, took on more bank debt after an owner’s wealth shock. Younger ones, on the other hand, saw a decrease in bank debt.

An important policy question, says Ring, is whether reduced business activity is driven more by financial forces or by psychological ones, such as a decrease in entrepreneurs’ willingness to take risks. 

His results suggest that financial constraints are more likely at play. That means government interventions, such as small-business lending subsidies, might help counter those constraints and help small businesses weather recessions. 

“Small businesses are important in most economies, and most of these firms rely heavily on their owners for financing,” Ring says. Owners can be a viable source of financing, but unfortunately, the owner’s personal wealth is likely to be hit at the same time as the firm is experiencing a downturn.” 

Entrepreneurial Wealth and Employment: Tracing Out the Effects of a Stock Market Crash” is published inThe Journal of Finance.

 


 

Copies of antibiotic resistance genes greatly elevated in humans and livestock


Study finds a smoking gun for the spread and evolution of antibiotic resistance


Peer-Reviewed Publication

DUKE UNIVERSITY




DURHAM, N.C. – Biomedical engineers at Duke University have uncovered a key link between the spread of antibiotic resistance genes and the evolution of resistance to new drugs in certain pathogens.

The research shows bacteria exposed to higher levels of antibiotics often harbor multiple identical copies of protective antibiotic resistance genes. These duplicated resistance genes are often linked to “jumping genes” called transposons that can move from strain to strain. Not only does this provide a mechanism for resistance to spread, having multiple copies of a resistance gene can also provide a handle for evolution to generate resistance to new types of drugs.

The results appeared February 16 in the journal Nature Communications.

Earlier work by the Lingchong You lab has shown that 25% of bacterial pathogens are capable of spreading antibiotic resistance through horizontal gene transfer. They have also shown that the presence of antibiotics does not speed up the rate of horizontal gene transfer, so there must be something else happening that pushes the genes to spread.

“Bacteria are constantly evolving under many pressures, and elevated duplication of certain genes is like a fingerprint left at the crime scene that allows us to see what kinds of functions are evolving really rapidly,” said Rohan Maddamsetti, a postdoctoral fellow working in the laboratory of Lingchong You, the James L. Meriam Distinguished Professor of Biomedical Engineering at Duke.

“We hypothesized that bacteria under attack from antibiotics would often have multiple copies of protective resistance genes, but until recently we didn’t have the technology to find the smoking gun.”

Traditional DNA-reading technology copies short snippets of genes and counts them up, making it hard to determine whether high counts of specific sequences are actually in the sample or if they are being artificially amplified by the reading process. In the past five years, however, complete genome sequencing with long-read technology has become more common, allowing researchers to spot high levels of genetic repetition.

In the study, Maddamsetti and coauthors counted the repetitions of resistance genes present in samples of bacterial pathogens taken from a variety of environments. They discovered that those living in places with higher levels of antibiotic use — humans and livestock — are enriched with multiple identical copies of antibiotic resistance genes, while such duplications are rare in bacteria living in wild plants, animals, soil and water.

“Most bacteria have some basic antibiotic resistance genes in them, but we rarely saw them being duplicated out in nature,” You said. “By contrast, we saw lots of duplication happening in humans and livestock where we’re likely hammering them with antibiotics.”

The researchers also found that the levels of resistance duplication were even higher in samples taken from clinical datasets where patients are likely taking antibiotics. This is an important point, they say, because the increase in copying antibiotic resistance genes also increases the likelihood of bacteria evolving resistance to new types of treatments.

“Constantly creating copies of genes for resistance to penicillin, for example, may be the first step toward being able to break down a new kind of drug,” Maddamsetti said. “It gives evolution more rolls of the dice to find a special mutation.”

“Everyone recognizes there is a growing antibiotic resistance crisis, and the knee jerk reaction is to develop new antibiotics,” You added. “But what we find time and again is that, if we can figure out how to use antibiotics more efficiently and effectively, we can potentially address this crisis much more effectively than simply developing new drugs.”

“The majority of antibiotics used in the United States are not used on patients, they’re used in agriculture,” You added. “So this is an especially important message for the livestock industry, which is a major driver of why antibiotic resistance is always out there and becoming more serious.”

This work was supported by the National Institutes of Health (R01AI125604, R01GM098642, R01EB031869).

CITATION: “Duplicated Antibiotic Resistance Genes Reveal Ongoing Selection and Horizontal Gene Transfer in Bacteria,” Rohan Maddamsetti, Yi Yao, Teng Wang, Junheng Gao, Vincent T. Huang, Grayson S. Hamrick, Hye-In Son & Lingchong You. Nature Communications, Feb. 16, 2024. DOI: 10.1038/s41467-024-45638-9

Online: https://www.nature.com/articles/s41467-024-45638-9

# # #