Science News

30 May. 2023

Anyons, anyone?

Scientists have created strange new particle-like objects called non-abelian anyons. These long-sought quasiparticles can be “braided,” meaning that they can be moved around one another and retain a memory of that swapping, similar to how a braided ponytail keeps a record of the order in which strands cross over each other.

Two independent teams — one led by researchers at Google, the other by researchers at the quantum computing company Quantinuum — have reported creating and braiding versions of these anyons using quantum computers. The Google and Quantinuum results, respectively reported May 11 in Nature and May 9 at, could help scientists construct quantum computers that are resistant to the errors that currently bedevil the machines.

Non-abelian anyons defy common intuition about what happens to objects that swap locations. Picture the street game with cups and balls, where a performer swaps identical cups back and forth. If you weren’t watching closely, you’d never know if two cups had been moved around one another and back to their original positions. In the quantum world, that’s not always the case.

“It’s predicted that there is this crazy particle where, if you swap them around each other while you have your eyes closed, you can actually tell after the fact,” says physicist Trond Andersen of Google Quantum AI in Santa Barbara, Calif. “This goes against our common sense, and it seems crazy.”

Particles in our regular 3-D world can’t do this magic trick. But when particles are confined to just two dimensions, the rules change. While scientists don’t have a 2-D universe in which to explore particles, they can manipulate materials or quantum computers to exhibit behavior like that of particles that live in two dimensions, creating objects known as quasiparticles.

All fundamental subatomic particles fall into two classes, based on how identical particles of each type behave when swapped. They are either fermions, a class that includes electrons and other particles that make up matter, or bosons, which include particles of light known as photons.

But in two dimensions, there’s another option: anyons. For bosons or fermions, swapping identical particles back and forth or moving them around one another can’t have a directly measurable effect. For anyons, it can.

In the 1990s, scientists realized that a specific version of an anyon, called a non-abelian anyon, could be used to build quantum computers that might safeguard fragile quantum information, which is easily knocked out of whack by minute disturbances.

“For fundamental reasons these anyons have been very exciting, and for practical reasons people hope they might be useful,” says theoretical physicist Maissam Barkeshli of the University of Maryland in College Park, who was not involved with either study.

Google’s team created the anyons using a superconducting quantum computer, where the quantum bits, or qubits, are made of material that conducts electricity without resistance. Quantinuum’s study, which has yet to be peer-reviewed, is based on a quantum computer whose qubits are composed of trapped, electrically charged atoms of ytterbium and barium. In both cases, scientists manipulated the qubits to create the anyons and move them around, demonstrating a measurable change after the anyons were braided.

Scientists have previously created and braided a less exotic type of anyon, called an abelian anyon, within a 2-D layer of a solid material (SN: 7/9/20). And many physicists are similarly questing after a solid material that might host the non-abelian type.

But the new studies create non-abelian states within qubits inside a quantum computer, which is fundamentally different, Barkeshli says. “You’re kind of synthetically creating the state for a fleeting moment.” That means it doesn’t have all the properties that anyons within a solid material would have, he says.

In both cases, much more work must be done before the anyons could create powerful, error-resistant quantum computers. Google’s study, in particular, produces an anyon that’s akin to a fish out of water. It’s a non-abelian within a more commonplace abelian framework. That means those anyons may not be as powerful for quantum computing, Barkeshli says.

It’s not all about practical usefulness. Demonstrating that non-abelian anyons really exist is fundamentally important, says Quantinuum’s Henrik Dreyer, a physicist in Munich. It “confirms that the rules of quantum mechanics apply in the way that we thought they would apply.”

30 May. 2023

While volunteering at the University of New Mexico’s Children’s Hospital in Albuquerque, Quinton Smith quickly realized that he could never be a physician.

Then an undergrad at the university, Smith was too sad seeing sick kids all the time. But, he thought, “maybe I can help them with science.”  

Smith had picked his major, chemical engineering, because he saw it as “a cooler way to go premed.” Though he ultimately landed in the lab instead of at the bedside, he has remained passionate about finding ways to cure what ails people.

Today, his lab at the University of California, Irvine uses tools often employed in fabricating tiny electronics to craft miniature, lab-grown organs that mimic their real-life counterparts. “Most of the time, when we study cells, we study them in a petri dish,” Smith says. “But that’s not their native form.” Prodding cells to assemble into these 3-D structures, called organoids, can give researchers a new way to study diseases and test potential treatments.

By combining Silicon Valley tech and stem cell biology, scientists are now “making tissues that look and react and function like human tissues,” Smith says. “And that hasn’t been done before.”

The power of stem cells

Smith’s work began in two dimensions. During his undergraduate studies, he spent two summers in the lab of biomedical engineer Sharon Gerecht, then at Johns Hopkins University. His project aimed to develop a device that could control oxygen and fluid flow inside minuscule chambers on silicon wafers, with the goal of mimicking the environment in which a blood vessel forms. It was there that Smith came to respect human induced pluripotent stem cells.

These stem cells are formed from body cells that are reprogrammed to an early, embryonic stage that can give rise to any cell type. “It just blew my mind that you can take these cells and turn them into anything,” Smith says. 

Smith ultimately returned to Gerecht’s lab for his Ph.D., exploring how physical and chemical cues can push these stem cells toward becoming blood vessels. Using a technique called micropatterning — where researchers stamp proteins on glass slides to help cells attach — he spurred cells to organize into the beginnings of artificial blood vessels. Depending on the pattern, the cells formed 2-D stars, circles or triangles, showing how cells come together to form such tubular structures.   

An image of three shapes, all blue with a green border. The triangle, star and circle all rest on a black background.
Using tiny micropatterns made of proteins, Smith and colleagues pushed human induced pluripotent stem cells to organize into triangles, stars and circles. Cells tagged fluorescent green, mostly at the edges, make a protein important for building blood vessels; red cells have a protein that helps muscles, including blood vessels, contract; and blue marks the nuclei of individual cells.Courtesy of Q. Smith

While a postdoc at MIT, he transitioned to 3-D, with a focus on liver organoids.

Like branching blood vessels, a network of bile ducts carry bile acid throughout the liver. This fluid helps the body digest and absorb fat. But artificial liver tissue doesn’t always re-create ducts that branch the way they do in the body. Cells growing in the lab “need a little bit of help,” Smith says. 

To get around the problems, Smith and his team pour a stiff gel around minuscule acupuncture needles to create channels. After the gel solidifies, the researchers seed stem cells inside and douse the cells in chemical cues to coax them to form ducts. “We can create on-demand bile ducts using an engineering approach,” he says.

This approach to making liver organoids is possible because Smith speaks the language of biology and the language of engineering, says biomedical engineer Sangeeta Bhatia, a Howard Hughes Medical Institute investigator at MIT and Smith’s postdoc mentor. He can call on his cell biology knowledge and leverage engineering techniques to study how specific cell types are organized to work together in the body.

For example, Smith’s lab now uses 3-D printing to ensure liver tissues grown in the lab, including blood vessels and bile ducts, organize in the right way. Such engineering techniques could help researchers study and pinpoint the root causes behind some liver diseases, such as fatty liver disease, Smith says. Comparing organoids grown from cells from healthy people with those grown from cells from patients with liver disease — including Hispanic people, who are disproportionately affected — may point to a mechanism.

Looking beyond the liver

But Smith isn’t restricting himself to the liver. He and his trainees are branching out to explore other tissues and diseases as well.

One of those pursuits is preeclampsia, a disease that affects pregnant women, and disproportionately African American women. Women with preeclampsia develop dangerously high blood pressure because the placenta is inflamed and constricting the mother’s blood vessels. Smith plans to examine lab-grown placentas to determine how environmental factors such as physical forces and chemical cues from the organ impact attached maternal blood vessels.

“We’re really excited about this work,” Smith says. It’s only recently that scientists have tricked stem cells to enter an earlier stage of development that can form placentas. These lab-grown placentas even produce human chorionic gonadotropin, the hormone responsible for positive pregnancy tests.

Yet another win for the power of stem cells.

Quinton Smith is one of this year’s SN 10: Scientists to Watch, our list of 10 early and mid-career scientists who are making extraordinary contributions to their field. We’ll be rolling out the full list throughout 2023.

Want to nominate someone for the SN 10? Send their name, affiliation and a few sentences about them and their work to

29 May. 2023

If you ever come across a Cooper’s black orchid in the wild, you probably would mistake it for a stick — or perhaps an odd potato if you dig a little underneath it. Unlike many others of its kind, this delicate flower is devoid of lush green leaves and flashy petals. Its stem lies on the floor of New Zealand’s broadleaf forests for most of the year, only popping up during the summer months to blossom with pendulous brown and white blooms. And rather than growing a tangle of roots, the orchid sprouts a pale brown tuber.

But the chances of encountering a Cooper’s black orchid (Gastrodia cooperae) are getting slimmer. Fewer than 250 adult plants have been found since botanist Carlos Lehnebach identified the species in 2016, and they live in only three sites across New Zealand. To make matters worse, feral pigs, rabbits and other animals like to nosh on the tubers. And the forests where the orchid grows are being cleared for farmland (SN: 12/21/20). In 2018, New Zealand’s Department of Conservation  classified the orchid as nationally critical, emphasizing its high risk of extinction.

At the Lions Ōtari Plant Conservation Laboratory in Wellington — part of the country’s only botanical garden focused on native plants — Lehnebach and colleagues are working to bring Cooper’s black orchid back from the brink (SN: 9/6/18).

From one of the lab’s three fridge-sized incubators, conservationist Jennifer Alderton-Moss pulls out dozens of petri dishes containing the orchids’ speck-sized seeds and root-emanating tubers.

A man and woman looking at plants, some marked with reddish pink tape
Jennifer Alderton-Moss and Carlos Lehnebach count the number of seed capsules on adult Gastrodia cooperae plants in a New Zealand forest, marked with reddish pink tape.Karin van der Walt

The researchers dissect the roots under a microscope to look for fungi that could help the seeds germinate. Early in life, most orchids rely on fungi for essential nutrients and minerals. To conserve Cooper’s black orchids, the team needs to identify exactly which fungal species supplies the plant with nutrients. DNA testing helps the team rule out known orchid pathogens. Potential candidates are then extracted from roots and grown on petri dishes. Once they’re mature enough, fungi get paired up with seeds on another dish.

“We’re working with a rare species, so we can’t just [take] hundreds of seeds,” says conservationist Karin van der Walt. The team first tested its methods on Gastrodia sesamoides, a common orchid that also grows tubers. “If we get it wrong, at least we’re not causing extinction,” she says.

It took the researchers about a year of trial-and-error to find the right germination method for Cooper’s black orchid. Once they did, they had to wait another two to four months for the seeds to sprout.

Alderton-Moss removes a dish from a resealable bag and points out a fungus, an orchid leaf for the fungus to feed on and a few seeds that have now developed into light brown tuberlike grains. Cooper’s black orchid may have finally found its perfect match in Resinicium bicolor.

Commonly known as white-rot fungus, R. bicolor is a scourge on Douglas fir trees — a farmed nonnative tree in New Zealand — but seems to provide Cooper’s black orchid seeds with the nutrients and minerals they need to germinate. The next step is to grow Cooper’s black orchid plants from seedlings. That will reveal whether the fungus that helps seeds germinate is the same one that sustains the adult plant.

In the meantime, seeds and fungi are kept in a chilly slumber in one of the lab’s sterile rooms. Seeds are stored inside an incubator at –18° Celsius, while fungi are stored inside a cryogenic container with liquid nitrogen at –200° C. “If we lose [the orchid entirely], we have seeds banked in the lab,” van der Walt says. “We can at least grow them back — we know we can get that far.”

Left: A fungus feeding on an orchid leaf in a petri dish. Right: A closeup of the tiny tubers of the orchid, shown as grayish blobs, with a scale marker indicating measurement in micrometers
In lab experiments, Resinicium fungi (shown feeding on an orchid leaf in a petri dish, left) helped the speck-sized seeds of Cooper’s black orchid (red arrows) germinate. It’s unclear whether this specific fungi support the tiny tubers (one shown closeup, right) as they grow into adult orchids.Jennifer Alderton-MossIn lab experiments, Resinicium fungi (shown feeding on an orchid leaf in a petri dish, left) helped the speck-sized seeds of Cooper’s black orchid (red arrows) germinate. It’s unclear whether this specific fungi support the tiny tubers (one shown closeup, right) as they grow into adult orchids.Jennifer Alderton-Moss

To test the viability of banked seeds and fungi, the team plans to thaw them at quarterly intervals to see how much they’ll grow.

Ultimately, researchers want to seed wild areas with this plant-fungi pair to boost the population — without all the lab steps. Though there are still other factors to work out to make wild growth a reality, the lab technique is “a powerful way to prevent extinction,” van der Walt says, not only for the Cooper’s black orchid but other endangered species, too.

26 May. 2023

It’s hard to know how busy this year’s Atlantic hurricane season will be, thanks to a rarely observed combination of ocean and climate conditions.

The Atlantic Ocean is in an active storm era, a yearslong period of increasing storm activity. Plus sea surface temperatures there are much higher than usual this year, which can fuel storms, Matthew Rosencrans, the lead hurricane forecaster for the U.S. National Oceanic and Atmospheric Administration, said May 25 at a news conference. But this year will also see the onset of an El Niño phase of the El Niño-Southern Oscillation ocean and climate pattern, which tends to suppress hurricane formation.

That’s not a scenario that has occurred in historical records often, Rosencrans said. “It’s definitely kind of a rare setup for this year.”

He and his colleagues reported that there’s a 40 percent chance that Atlantic hurricane activity will be near normal this year. Near normal is actually unusually high for an El Niño year. But there’s also a 30 percent chance that activity will be above normal, and a 30 percent chance it’ll be below normal.

Overall, the agency is predicting 12 to 17 named storms, of which five to nine are predicted to become hurricanes, with sustained wind speeds of at least 119 kilometers per hour (74 miles per hour). Between one and four of those hurricanes could be category 3 or greater, with wind speeds of at least 178 kph (111 mph). The Atlantic hurricane season officially begins on June 1 and ends November 30.

There’s little consensus among other groups’ predictions, in part due to the uncertainty of what role El Niño will play. On April 13, Colorado State University, in Fort Collins, announced that it anticipated a below-average season, with just 13 named storms, including six hurricanes. On May 26, the U.K. Meteorological Office announced that it predicts an extremely busy hurricane season in the Atlantic, with 20 named storms, including 11 hurricanes, of which five could be category 3 or greater. The long-term average from 1991 to 2020 is 14 named storms.

So far, 23 different groups have submitted predictions for the 2023 Atlantic season to a platform hosted by the Barcelona Supercomputing Center in Spain, which allows users to compare and contrast the various predictions. There’s a large spread among these predictions, ranging “from below average to well above average,” says Philip Klotzbach, an atmospheric scientist at Colorado State University who is responsible for the group’s seasonal Atlantic hurricane forecasts.

That spread is likely the result of two big sources of uncertainty, Klotzbach says: the strength of the El Niño (and when during the year it’s expected to develop), and whether the Atlantic’s surface water temperatures will stay above average.

Each group’s forecast is based on a compilation of many different computer simulations of ocean and atmospheric conditions that might develop during the hurricane season. How often those models agree leads to a probability estimate. NOAA’s models struggled to agree: “That’s why probabilities are not 60 to 70 percent,” Rosencrans said. “That’s to reflect there’s a lot of uncertainty this year in the outlook.”

An emerging El Niño phase is signaled by abnormally warm waters in the equatorial Pacific Ocean, which in turn is tied to shifts in wind strength and humidity around the globe. One of the ways that El Niño tinkers with climate is that it alters the strength of winds in the upper atmosphere over the northern Atlantic Ocean. Those stronger winds can shear off the tops of developing storms, hampering hurricane formation. Warmer ocean waters like those in the Atlantic right now, on the other hand, fuel hurricanes by adding energy to storm systems. How active a season it will be depends on which of those two forces will prevail.

The Met Office, for example, reported that its climate simulations suggest that the wind shear due to this year’s El Niño will be relatively weak, while surface ocean temperatures will remain well above average. Similarly anomalously warm waters in 2017 were found the be the primary cause behind that year’s glut of intense Atlantic hurricanes (SN: 9/28/18).

In the future, hurricane forecasts could become ever more uncertain. It’s unknown how climate change will affect large-scale ocean and climate patterns such as the El Niño-Southern Oscillation in general (SN: 8/21/19). Computer simulations have suggested that as the atmosphere warms, these globe-scale “teleconnections” may become somewhat disconnected, which also makes them potentially harder to predict (SN: 2/13/23). Climate change is also expected to increase ocean temperatures.

Meanwhile, on the other side of the world, the Pacific Ocean’s hurricane season has already begun with a powerful storm, Super Typhoon Mawar, which battered Guam as a category 4 cyclone before roaring toward the Philippines on May 25, strengthening to category 5.

26 May. 2023

Planetary scientists now know how thick the Martian crust is, thanks to the strongest Marsquake ever observed.

On average, the crust is between 42 and 56 kilometers thick, researchers report in a paper to appear in Geophysical Research Letters. That’s roughly 70 percent thicker than the average continental crust on Earth.

The measurement was based on data from NASA’s InSight lander, a stationary seismometer that recorded waves rippling through Mars’ interior for four Earth years. Last May, the entire planet shook with a magnitude 4.7 quake that lasted more than six hours (SN: 5/13/22). “We were really fortunate that we got this quake,” says seismologist Doyeon Kim of ETH Zurich.

InSight recorded seismic waves from the quake that circled Mars up to three times. That let Kim and colleagues infer the crust thickness over the whole planet.

Not only is the crust thicker than that of the Earth and the moon, but it’s also inconsistent across the Red Planet, the team found. And that might explain a known north-south elevation difference on Mars.

Topological and gravity data from Mars orbiters have shown that the planet’s northern hemisphere is substantially lower than the southern one. Researchers had suspected that density might play a part: Perhaps the rocks that make up northern Mars have a different density than those of southern Mars.

But the crust is thinner in the northern hemisphere, Kim and colleagues found, so the rocks in both hemispheres probably have the same average densities. That finding helps scientists narrow down the explanations for why the difference exists in the first place.

Knowing the crust’s depth, the team also calculated that much of Mars’ internal heat probably originates in the crust. Most of this heat comes from radioactive elements such as potassium, uranium and thorium. An estimated 50 to 70 percent of those elements are probably in the crust rather than the underlying mantle, computer simulations suggest. That supports the idea that parts of Mars still have volcanic activity, contrary to a long-held belief that the Red Planet is dead (SN: 11/3/22).  

26 May. 2023

Meet the house that diapers built.

Researchers have designed and erected a house that has shredded, disposable diapers mixed into its concrete and mortar. A single-story home of about 36 square meters can pack nearly 2 cubic meters of used diapers into its floors, columns and walls, the team reports May 18 in Scientific Reports.

Using recycled diapers as composite building materials would not only shrink landfill waste but also could make such homes more affordable, the team says, a particular need in developing countries like Indonesia where the demand for low-cost housing far outstrips the supply.

Indonesia’s urban population has increased by about 4 percent per year in the last three decades, and more of its people are moving to urban centers. Over two-thirds of Indonesians are expected to live in urban areas by 2025, says environmental engineer Siswanti Zuraida of the University of Kitakyushu in Japan. That population boom is putting a heavy strain on both housing demand and waste management, says Zuraida, who is originally from Indonesia. Used disposable diapers mostly pile up in landfills or get incinerated, adding to a growing waste problem.

The materials used to build a house, meanwhile, particularly those needed to shore up its structural integrity, are often the biggest barrier to making homes affordable. So researchers have previously examined the possibility of using a wide variety of unconventional materials that could also save costs. These materials included many that would otherwise pile up as waste, such as the husks of rice grains or fly ash, the fine residue left over from the combustion of pulverized coal. Disposable diapers, as it happens, contain a lot of potentially useful building material, such as wood pulp, cotton, rayon and plastic.

Zuraida and colleagues assessed how much of the sand, gravel and other traditional building materials used in mortar and concrete could be replaced by diapers — washed, dried, sterilized and shredded — without reducing the strength of the structures. They created six different samples of concrete and mortar by mixing different proportions of diaper material with cement, sand, gravel and water. Crushing the samples in a machine let the researchers test how much weight each could bear.

The team then went on to design — and then build — a small, single-story, two-bedroom, one-bathroom home based on the maximum amount of diaper waste they calculated they could use. Recycled diapers could replace up to 27 percent of the traditional materials used in load-bearing structural components like columns and beams without losing significant strength, the team found. For buildings with more floors, that fraction is somewhat less: A three-story home could use up to 10 percent disposable diapers in its load-bearing structures, the team calculated. As for nonstructural components like wall partitions or garden paving blocks, shredded diapers could replace up to 40 percent of the sand.

Despite the need for more affordable housing, there are significant hitches that stand in the way of adopting diapers or other low-impact nonconventional materials, Zuraida says.

Diapers’ plastic components would have to be separated from the organic fibers, a complicated recycling process currently available only in developed nations. And Indonesia’s building regulations restrict construction materials to concrete, bricks, wood and ceramics — materials that also bear a high cost in terms of carbon emissions.

“Thinking about how to use waste for other purposes is an excellent idea,” says chemist Christof Schröfl of Technische Universität Dresden in Germany. But there may be limits on the ultimate environmental friendliness of repurposing used diapers in buildings, he says, due to the existing challenges of separating and sanitizing diapers in waste. “It’s maybe worthwhile to start thinking about ways to replace single-use diapers” with something less frequently disposed of.

25 May. 2023

Giardia has plagued people for a long time.

The parasite can bring about dysentery — a miserable (and occasionally deadly) mixture of diarrhea, cramps and fever. Scientists have now uncovered traces of the giardia parasite in the remains of two roughly 2,600-year-old toilets once used by the wealthy denizens of Jerusalem. The remains are the oldest known biological evidence of giardia anywhere in the world, researchers report May 25 in Parasitology.

The single-cell parasite Giardia duodenalis can be found today in human guts around the planet. This wasn’t always the case — but working out how pathogens made their debut and moved around is no easy feat (SN: 2/2/22). While some intestinal parasites can be preserved for centuries in the ground, others, like giardia, quickly disintegrate and can’t be spotted under a microscope.

In 1991 and 2019, archeologists working at two sites in Jerusalem came across stone toilet seats in the remains of mansionlike homes. These “were quite posh toilets” used by “swanky people,” says Piers Mitchel, a paleoparasitolgist at the University of Cambridge.

The original excavators of soil taken from beneath the seats of these toilets glimpsed traces of roundworm and other possible intestinal parasites in soil samples put under a microscope. Mitchel and his colleagues built on this analysis by using antibodies to search for the remains of giardia and two other fragile parasites in the millennia-old decomposed feces under both seats.

There was “plenty of doubt” that giardia was around in Jerusalem at the time because it’s so hard to reconstruct the movement of ancient disease, Mitchel says.

But the find hints that it was a regular presence in the region, says Mattieu le Bailly, a paleoparasitolgist at the University Bourgogne Franche-Comté in Besançon, France, who was not involved in the study.

The idea that a pathogen like giardia, which spreads via contaminated water and sometimes flies, existed and was possibly widespread in ancient Jerusalem makes a lot of sense, Mitchel says, given the hot, dry, insect-ridden climate around the Iron Age city.

25 May. 2023

Microbial stress can be a boon for young trees.

Saplings grown in soil microbes that have experienced drought, cold or heat are more likely to survive when faced with those same conditions, researchers report in the May 26 Science. And follow-up tests suggest that the microbes’ protective relationship with trees may linger beyond initial planting.   

The team’s findings could aid massive tree planting efforts by giving new saplings the best chance of survival over the long run, says Ian Sanders, a plant and fungal ecologist at the University of Lausanne in Switzerland. “If you can control which microbes are put onto tree saplings in a nursery, you can probably help to determine whether they’re going to survive or not when they’re transplanted to the field.”

As climate change pushes global temperatures ever higher, many species must either adapt to new conditions or follow their ideal climate to new places (SN: 1/25/23). While forests’ ranges have changed as Earth’s climate has warmed and cooled over hundreds of millions of years, the pace of current climate change is too fast for trees to keep up (SN: 4/1/20).

Trees live a long time, and they don’t move or evolve very quickly, says Richard Lankau, a forest ecologist at the University of Wisconsin–Madison. They do have close relationships with fast-adapting soil microbes, including fungi, which can help plants survive stressful conditions.

But it was unclear whether microbes that had previously survived various climates and stresses might give inexperienced baby trees encountering a changing climate a leg up. With friends in the soil, “trees might have more tools in their toolkit than we give them credit for” to survive tough conditions, Lankau says.

For the study, Lankau and fellow ecologists Cassandra Allsup and Isabelle George — both also at UW–Madison — collected soil from 12 spots in Wisconsin and Illinois that varied in temperature and amount of rain. The team then used the soils to plant an abundance of 12 native tree species, including white oak (Quercus alba) and silver maple (Acer saccharinum). Overall, “we had thousands of plants we were monitoring,” Allsup says.

Those saplings grew in the soils in a greenhouse for two months before being transplanted in one of two field sites — one warm and one cold. To simulate drought, some trees in each spot were placed under transparent plastic sheets that blocked direct rainfall.

One site in northern Wisconsin was at the northern edge of the trees’ range and represented how trees might take root in a new area that’s getting warm enough for them to grow. There, trees planted in soil containing cold-adapted microbes better survived Wisconsin’s frigid winter temperatures. Plants that faced drought in addition to the cold, on the other hand, didn’t have the same benefit.

The other location, set up in central Illinois, was designed to represent a region where the climate is getting too hot or dry for the tree species to tolerate. Saplings grown in soil with microbes from arid spots were more likely to survive a lack of rain. But those grown in soils with heat-tolerant microbes were only slightly more likely to survive when they received normal rainfall. 

A close up photo of a jack-o’-lantern mushroom.
Some fungi, including this jack-o’-lantern mushroom (Omphalotus illudens), have a close relationship with trees. That connection could help saplings expand their range amid changing climate.Cassandra Allsup

Resident species already living in the area didn’t outcompete all of the transplanted microbes. Newly introduced fungi persisted in the soil for three years, a sign that any protective effects might last at least that long, the team found. 

It’s still unclear which microbes best aid the trees. Analyses of microbes living in the soil hinted that fungi that live inside plant roots may better help trees survive drought. Cold-adapted soils seem to have fewer fungal species. But soils also contain bacteria, archaea and protists, Sanders says. “We don’t know what it is yet that seems to affect the plant survival in these changing climates.”

Determining which microbes are the important ones and whether there are specific conditions that best suit the soil is next up on the list, Allsup says. For example, can dry-adapted soil from Iowa help when planting trees in Illinois? “We need to think more about soils and combinations and [transplant] success… to actually save the forest.”

One caution, Sanders says, is that transporting microbes from one place to another en masse could bring the bad along with the good. Some microbes might be pathogens in the new place where they’re transplanted. “That’s also a big danger.” 

25 May. 2023

More than 5,000 animal species previously unknown to science live in a pristine part of the deep sea.

Their home — called the Clarion-Clipperton Zone — sits in the central and eastern Pacific Ocean between Hawaii and Mexico. The zone is roughly twice the size of India, sits 4,000 to 6,000 meters deep and is largely a mystery, like much of the deep sea.

In a new study, scientists amassed and analyzed more than 100,000 published records of animals found in the zone, with some records dating back to the 1870s. About 90 percent of species from these records were previously undescribed: There were only about 440 named species compared with roughly 5,100 without scientific names. Worms and arthropods make up the bulk of the undescribed creatures, but other animals found there include sponges, sea cucumbers and corals, the researchers report May 25 in Current Biology.

“The diversity down there does surprise me,” says study coauthor Muriel Rabone, a data analyst and biologist at the Natural History Museum in London. “It’s just astonishing.”

Due to its rich content of minerals like cobalt and nickel, the Clarion-Clipperton Zone is sought after by mining companies. About a sixth of it, roughly a million square kilometers, has already been promised to companies for exploration.

Many of the named species in the new study have been found only in the zone, emphasizing how important it is to establish a biodiversity baseline for the area before mining starts, Rabone says. But the area is deep and remote, making data collection there difficult and expensive (SN: 11/10/17).

What’s more, deep-sea ecosystems are connected to the ecosystems above them, Rabone says, such as through nutrient cycling. Scientists need to understand more about the Clarion-Clipperton Zone and areas like it to anticipate how the effects of mining may bubble up to the ocean surface.

24 May. 2023

Beer breweries’ trash may have been Danish painters’ treasure.

The base layer of several paintings created in Denmark in the mid-1800s contains remnants of cereal grains and brewer’s yeast, the latter being a common by-product of the beer brewing process, researchers report May 24 in Science Advances. The finding hints that artists may have used the leftovers to prime their canvases.  

Records suggest that Danish house painters sometimes created glossy, decorative paint by adding beer, says Cecil Krarup Andersen, a conservator at the Royal Danish Academy in Copenhagen. But yeast and cereal grains have never been found in primer.

Andersen had been studying paintings from the Danish Golden Age, an explosion of artistic creativity in the first half of the 19th century, at the National Gallery of Denmark. Understanding these paintings’ chemical compositions is key to preserving them, she says. As part of this work, she and colleagues looked at 10 pieces by Christoffer Wilhelm Eckersberg, considered the father of Danish painting, and his protégé Christen Schiellerup Købke.

Canvas trimmings from an earlier conservation effort allowed for an in-depth analysis that wouldn’t have otherwise been possible, since the process destroys samples. In seven paintings, Saccharomyces cerevisiae proteins turned up, as well as various combinations of wheat, barley, buckwheat and rye proteins. All these proteins are involved in beer fermentation (SN: 9/19/17).

Tests of an experimental primer that the researchers whipped up using residual yeast from modern beer brewing showed that the mixture held together and provided a stable painting surface — a primary purpose of a primer. And this concoction worked much better than one made with beer.

Beer was the most common drink in 1800s Denmark, and it was akin to liquid gold. Water needed to be treated prior to consuming and the brewing process took care of that. As a result, plenty of residual yeast would have been available for artists to purchase, the researchers say.

If the beer by-product is found in paintings by other artists, Andersen says, that information can help conservators better preserve the works and better understand the artists’ lives and craftsmanship. “It’s another piece of the puzzle.”

24 May. 2023

A system that restores communication between the brain and spine has enabled a man paralyzed by a spinal cord injury to regain near-natural walking ability.

Once the patient’s brain activity was decoded, the brain-spine interface took mere minutes to calibrate, after which the man reported natural-feeling control over movements. He still needs crutches but can easily navigate ramps and steps, surpassing gains from previous treatments, researchers report May 24 in Nature.

“The results are consistent with what I’d hope would happen, which is encouraging,” says V. Reggie Edgerton, a physiologist at Rancho Los Amigos National Rehabilitation Center in Downey, Calif., who was not involved in the study. Still, in terms of treating spinal cord paralysis, he says, “we’re at the stage of the Wright brothers and flight.”

Spinal cord injuries can interrupt communication between the brain and spine, causing paralysis. Previous research showed that stimulating spinal cord nerves can produce movement (SN: 8/3/22), but this is the first time that a patient’s own brain activity has been used to re-establish voluntary control of leg movements.

A biking accident 12 years ago left the 40-year-old man, who prefers to be identified by his first name, Gert-Jan, paralyzed with an incomplete spinal cord injury. Six years later, he enrolled in a clinical trial involving a spinal cord implant that stimulates nerves that control leg movements. He regained the ability to step with a walker, but this involved making unnatural heel movements, picked up by motion sensors, to trigger preprogrammed nerve stimulation patterns. He had difficulty starting and stopping, and could walk only over flat surfaces.

The new study aimed to hand control over to Gert-Jan’s brain. “Despite using the [spinal cord implant] stimulation for three years, he hit a plateau in his recovery, and became interested in using the new brain-controlled stimulation,” says Grégoire Courtine, a neuroscientist at the École Polytechnique Fédérale de Lausanne in Switzerland. “So he became our first test pilot.”

Courtine and colleagues added a brain implant to create a system that translates thought into movement. Two electrode arrays that sit on the surface of the brain record activity from the sensorimotor cortex, a region of the brain that helps direct muscle movements. These signals are sent wirelessly to a processing unit that converts them into stimulation patterns, which are transmitted to the spinal cord implant.

After implantation, Courtine and colleagues asked Gert-Jan to attempt leg joint movements while they analyzed his brain activity. Different patterns of activity differentiated hip, knee and ankle movements, the researchers found, enabling them to map brain signals to intended movements. The team created stimulation patterns targeting muscles that control putting weight down, pushing forward and leg swings, to reproduce walking motions. During use, an artificial intelligence algorithm translates incoming brain signals into appropriate command signals for the spinal implant.

The researchers calibrated the system so that Gert-Jan could control the amount of movement. “This brings a more fluid walking pattern,” Courtine says, helping him adapt his foot placement and even climb staircases.

“The stimulation before was controlling me, and now I’m controlling the stimulation,” Gert-Jan said May 23 during a news conference.

A “neurorehabilitation” training program while using the device led to mobility improvements even with the brain-spine interface turned off, the researchers found. “This suggests new nerve connections developed,” Courtine says.

Researchers need to understand more about how this recovery works. “The question is: Where in the brain is getting connected to where in the spinal cord? And we don’t really know that,” Edgerton says. “We need to figure out how the two are working together.”

The extent of Gert-Jan’s recovery delivered quality-of-life boosts, such as moving around the house independently, or standing at a bar drinking with friends. “That’s the goal of a lot of people who are completely paralyzed,” Edgerton says. “To be standing at a bar, looking people eye to eye.” While many paralyzed people prioritize other problems, such as bathroom function and blood pressure, this study aimed only to restore mobility.

Gert-Jan has been using the system for nearly two years now, Courtine says, and the brain implant has remained stable and reliable.

The researchers think the approach will work for other patients, but caution that the extent of recovery may depend on the severity of injury. “You have to be careful to calibrate expectations,” Courtine says. “But I’m confident we can reproduce the same outcome, especially in individuals with incomplete spinal cord injury.”

The team plans to apply the approach to the upper limbs too, neuroscientist Henri Lorach, also at the École Polytechnique Fédérale de Lausanne, said during the news conference. “We are initiating a clinical trial in three participants that will target these circuits.” It may also be possible to treat paralysis caused by stroke, the researchers say.

Courtine and colleagues developed a version of the system that Gert-Jan could operate himself at home, but further improvements are still needed. The processing unit is bulky, for example, and the brain implant involves two 5-centimeter-wide cylinders that sit in holes cut in the skull.

Onward Medical, a Lausanne-based company cofounded by Courtine, is working on miniaturizing the brain implant and processing unit, Courtine says, to develop a commercial version that “is easy for patients to use in daily life.”

24 May. 2023

The spiny mouse is an unassuming rodent, but it’s armed with a very special tail.

CT scans show the tail is sheathed in a secret blanket of bony plates. Before the scans, only one other group of modern mammals was known to wield this kind of armor: armadillos. The discovery, reported May 24 in iScience, may mean that the skin bones are more widespread in mammals than previously thought and could shed light on their evolution. 

The rodent’s secret was revealed when evolutionary biologist Edward Stanley of the Florida Museum of Natural History in Gainesville put a museum specimen of a spiny mouse (Acomys spp.) in an X-ray machine as part of a multi-institutional project to develop 3-D digital models of all vertebrate life.

It was a “nondescript looking” mouse with slightly spiky fur, Stanley says. But in the initial X-ray, its tail looked unusual. “It looked kind of dark and weird,” he says.

A more detailed CT scan showed the mouse’s whole tail was covered in overlapping bony plates within the skin, under the surface layers.

To understand how the bony plates develop, Stanley and his colleagues teamed with Malcolm Maden, a developmental biologist at the University of Florida. The team scanned the tails of newborn spiny mice up to those that were 6 weeks old. Bony plates form first near the base of the tail and then as the mouse ages, grow down the tail to its tip. CT scans revealed that three other species in the same subfamily as the spiny mouse also have armor-studded tails. 

These bony plates, called osteoderms, may help keep spiny mice and their relatives alive. The rodents’ skin is especially fragile and easily tears off, particularly on the tail. It’s hypothesized that the tearaway skin is a macabre defense, where attacking predators are left with a mouthful or paw full of shed skin. The plates may prevent predators from piercing too deep.

“If you can stop the teeth or the claws of your predator at the tearaway boundary, then it’s much easier to get away,” Stanley explains. The mice regenerate the lost skin later.

But the tail’s skin bones might protect against more than just predators. For some reason, spiny mice routinely bite each other’s tails, says Ashley Seifert, a developmental biologist at the University of Kentucky in Lexington. “So maybe they have evolved osteoderms as armament, but to defend their tails from each other instead of predators.”

To better understand the biological underpinnings of the bony skin, the researchers took skin samples from the tails of newborn spiny mice in places with and without osteoderms and analyzed gene activity. 

In skin samples with osteoderms, the activity of a suite of genes associated with bone cell development was boosted compared with samples without osteoderms. But the activity of genes that make keratin, a key building block for skin, was ramped down. The next step, Maden says, is to see how all these genes actually grow the osteoderms.

The research could help provide insights into osteoderm evolution. Bony skin is found in a variety of reptile groups, having evolved independently in crocodilians, many different lizard groups and some dinosaurs (but no birds) (SN: 12/6/22). Madagascar’s fish-scaled geckos have osteoderms and shed skin like spiny mice. Aside from the rodents in the new study and armadillos, the only other known mammals with bony skin are all extinct: an ancient hedgehog-like animal called Pholidocercus, ground sloths and armadillo relatives called glyptodonts (SN: 2/22/16).

Delving into gene activity patterns is rarely done in osteoderm research, says Chris Broeckhoven, an evolutionary biologist at the University of Antwerp in Belgium. Having this comparative data from mice available could yield key evolutionary insights.

One key insight, Maden says, could be “why [osteoderms] keep appearing in evolution and then disappear.”

It’s also possible osteoderms are more common among vertebrates than previously thought. No snakes were known to have the bony skin and then in April researchers reported finding them in sand boas.

These discoveries are “a good example of how you should look at the world around you,” Maden says. “Who knows what you will discover.”

23 May. 2023

On Jupiter, lightning jerks and jolts a lot like it does on Earth.

Jovian lightning emits radio wave pulses that are typically separated by about one millisecond, researchers report May 23 in Nature Communications. The energetic prestissimo, the scientists say, is a sign that the gas giant’s lightning propagates in pulses, at a pace comparable to that of the bolts that cavort through our own planet’s thunderclouds. The similarities between the two world’s electrical phenomena could have implications for the search for alien life.

Arcs of lightning on both worlds appear to move somewhat like a winded hiker going up a mountain, pausing after each step to catch their breath, says Ivana Kolmašová, an atmospheric physicist at the Czech Academy of Sciences in Prague. “One step, another step, then another step … and so on.”

Here on Earth, lightning forms as turbulent winds within thunderclouds cause many ice crystals and water droplets to rub together, become charged and then move to opposite sides of the clouds, progressively generating static electrical charges. When the charges grow big enough to overcome the air’s ability to insulate them, electrons are released — the lightning takes its first step. From there, the surging electrons will repeatedly ionize the air and rush into it, lurching the bolt forward at an average of hundreds of thousands of meters per second.

Scientists have suggested that superbolts observed in Jovian clouds might also form by collisions between ice crystals and water droplets (SN: 8/5/20). But no one knew whether the alien bolts extended and branched in increments, as they do on Earth, or if they took some other form.

For the new study, Kolmašová and her colleagues used five years of radio wave data collected by NASA’s Juno spacecraft (SN: 12/15/22). Analyzing hundreds of thousands of radio wave snapshots, the team found radio wave emissions from Jovian lightning appeared to pulse at a rate comparable to that of Earth’s intracloud lightning — arcs of electricity that never strike ground. 

If bolts extend through Jupiter’s water clouds at a similar velocity as they do in Earth’s clouds, then Jovian lightning might branch and extend in steps that are hundreds to thousands of meters long. That’s comparable in length to the jolted strides of Earth’s intracloud lightning, the researchers say.

“That’s a perfectly reasonable explanation,” says atmospheric physicist Richard Sonnenfeld of the New Mexico Institute of Mining and Technology in Socorro, who wasn’t involved in the study. Alternatively, he says, the signals could be produced as pulses of electrical current propagate back and forth along tendrils of lightning that have already formed, rather than from the stop-and-go advancements of a new bolt. On Earth, such currents cause some bolts to appear to flicker.

But stop and go seems like a sound interpretation, says atmospheric physicist Yoav Yair of Reichman University in Herzliya, Israel. Kolmašová and her colleagues “show that if you’re discharging a cloud … the physics remains basically the same [on Jupiter as on Earth], and the current will behave the same.”

If that universality is real, it could have implications for the search for life elsewhere. Experiments have shown that lightning strikes on Earth could have smelted some of the chemical ingredients needed to form the building blocks of life (SN: 3/16/21). If lightning is discharging in a similar way on alien worlds, Yair says, then it could be producing similar ingredients in those places too.

23 May. 2023

Deblina Sarkar makes little machines, for which she has big dreams. The machines are so little, in fact, that they can humbly inhabit living cells. And her dreams are so big, they may one day save your mind.

Sarkar is a nanotechnologist and assistant professor at MIT. She develops ultratiny electronic devices, some smaller than a mote of dust, that she hopes will one day enter the brain. She’s also a fan of Kung Fu movies and likes to dance her own twist on bharata natya, a classical Indian dance form. Occasionally she goes hiking with her graduate students, once taking them as far as Yellowstone. Building camaraderie is vital, Sarkar says. But “I’m probably working day and night on my research,” she confesses. “There is an urgent problem at hand.”

That problem is Alzheimer’s disease, Parkinson’s disease and other neurological afflictions that assault the minds of millions of people worldwide. Sarkar’s solution: Employ minute machines to detect and reverse these disorders.

“She was always interested in applying … electronics to biological systems,” says collaborator and bioengineering researcher Samir Mitragotri of Harvard University, who has known Sarkar for about a decade and was on her thesis committee. She envisions using her tools to “transform how people are conducting biology,” he says, “bridging the worlds.”

A focus on nanoelectronics

Born in Kolkata, India, Sarkar credits both of her parents as early inspirations. Her boldness as a researcher comes from her mother, who as a young woman defied social norms in her village by working to fund her own education and speaking out against the dowry system. Meanwhile, Sarkar’s father sparked her fascination for engineering.

At the age of 15, he abandoned his dreams of becoming an engineer to find other jobs; he needed to support his parents and the rest of his family after his father, an Indian freedom fighter, was shot in the leg and could no longer work. Still, Sarkar recalls her father finding time for his passion, fashioning devices to make home life more convenient. These included an electricity-free washing machine and vehicles that could freight hefty loads down local byroads to their house.

“That got me very, very interested in science and technology,” Sarkar says. “Engineering specifically.”

After earning a bachelor’s degree in electrical engineering from the Indian Institute of Technology Dhanbad, Sarkar moved to California to study nanoelectronics at the University of California, Santa Barbara. There, she tested new ways to create nanodevices that could reduce the amount of power consumed by computers and other everyday electronics.

One standout device Sarkar developed during her graduate work was a transistor that reduced the amount of power lost as heat by 90 percent compared with some of today’s most common silicon transistors (SN: 3/18/22). For the breakthrough, UC Santa Barbara awarded Sarkar’s Ph.D. dissertation the Lancaster Award for its impact in advancing math, physical sciences and engineering.

When tech meets the body

Along the way, Sarkar became fascinated with the brain, which she calls “the lowest energy computer.” A project imaging amyloid-beta plaques as a postdoc at MIT opened the door to fusing her dual interests, and she stayed on as an assistant professor to found the Nano-Cybernetic Biotrek group. Her group develops nanodevices that can interface with living cells, and “neuromorphic” computing devices, which have architectures inspired by the human brain and nervous system.  

So far, the group’s most innovative device may be the Cell Rover, a flat antenna that could monitor processes inside cells. For a study reported in 2022, Sarkar and her colleagues used magnetic fields to finesse a Cell Rover, roughly the size of a tardigrade, into a mature frog egg cell. The team demonstrated that when stimulated by a magnetic field created by an alternating current, molecules in the nanodevice vibrated at frequencies safe for living cells. Using a wire coil receiver, the researchers were able to detect how those vibrations affected the device’s own magnetic field, thus showing it could communicate with the outside world. Cell Rovers could be outfitted with films that latch onto and detect select proteins or other biomolecules.

Sarkar envisions using the device to spot misfolded proteins in the brain that may be early signs of Alzheimer’s disease. Today, memory loss is the only way to know a living person has Alzheimer’s, but by then, the damage is irreversible, Sarkar says. Cell Rovers could also be paired with nanodevices that harvest energy from and electrically stimulate cells, opening the door for new types of brain electrodes and subcellular pacemakers. Or fleets of remotely controlled devices could replace invasive surgeries — detecting a small tumor growing in the brain, for example, and maybe even killing it.

Two illustrations of the Cell Rover. The top image has several small blue and red rectangles randomly scattered in a white box. The bottom image has those same small rectangles in an organized grid, six across and four down.
When left undisturbed, the magnetic molecules in the Cell Rover are randomly oriented (top). But when subjected to a magnetic field produced by an alternating current, they will repeatedly flip around and reorient themselves (bottom). Those movements strain the device and cause it to vibrate in ways the researchers can detect.B. Joy et al/Nature Communications 2022When left undisturbed, the magnetic molecules in the Cell Rover are randomly oriented (top). But when subjected to a magnetic field produced by an alternating current, they will repeatedly flip around and reorient themselves (bottom). Those movements strain the device and cause it to vibrate in ways the researchers can detect.B. Joy et al/Nature Communications 2022

She’s essentially establishing a new field of science, at the intersection of nanoelectronics and biology, Mitragotri says. “There are many opportunities for the future.”

One day, Sarkar hopes to insert nanodevices between human neurons to boost the computing speed of the fleshy processor already in our skulls. Our brains are remarkable, she says, but “we could be better than what we are.”

Deblina Sarkar is one of this year’s SN 10: Scientists to Watch, our list of 10 early and mid-career scientists who are making extraordinary contributions to their field. We’ll be rolling out the full list throughout 2023.

Want to nominate someone for the SN 10? Send their name, affiliation and a few sentences about them and their work to

22 May. 2023

Scientists can see chronic pain in the brain with new clarity.

Over months, electrodes implanted in the brains of four people picked up specific signs of their persistent pain. This detailed view of chronic pain, described May 22 in Nature Neuroscience, suggests new ways to curtail the devastating condition. 

The approach “provides a way into the brain to track pain,” says Katherine Martucci, a neuroscientist who studies chronic pain at Duke University School of Medicine.

Chronic pain is incredibly common. In the United States from 2019 to 2020, more adults were diagnosed with chronic pain than with diabetes, depression or high blood pressure, researchers reported May 16 in JAMA Network Open. Chronic pain is also incredibly complex, an amalgam influenced by the body, brain, context, emotions and expectations, Martucci says. That complexity makes chronic pain seemingly invisible to an outsider, and very difficult to treat.

One treatment approach is to stimulate the brain with electricity. As part of a clinical trial, researchers at the University of California, San Francisco implanted four electrode wires into the brains of four volunteers with chronic pain. These electrodes can both monitor and stimulate nerve cells in two brain areas: the orbitofrontal cortex, or OFC, and the anterior cingulate cortex, or ACC. The OFC isn’t known to be a key pain influencer in the brain, but this region has lots of neural connections to pain-related areas, including the ACC, which is thought to be involved in how people experience pain.

An x-ray image of a person's head, neck and shoulders. Two boxes with wires are attached to the head and red lines appear on the skull.
Four thin wires with electrodes (red) were implanted into the brain of a research participant with chronic pain. These electrodes are controlled by two devices implanted on the upper chest.P. Shirvalkar

But before researchers stimulated the brain, they needed to know how chronic pain was affecting it. For about 3 to 6 months, the implanted electrodes monitored brain signals of these people as they went about their lives. During that time, the participants rated their pain on standard scales two to eight times a day.

Using sophisticated machine learning approaches, researchers then linked each person’s pain ratings to their brain activity patterns, ultimately landing on a signature of each person’s chronic pain.

In many ways, the patterns were unique to each person, but there was overlap: Brain activity in the OFC, an area at the front of the brain just behind the eyes, tracked with people’s chronic pain levels. Some unexpected pain patterns cropped up along the way, too. Two volunteers’ pain fluctuated on a roughly three-day cycle, for instance.

Brain activity in the OFC could represent a solid biomarker of chronic pain, a signal that could both help doctors track treatment responses and serve as new targets for treatment, says neuroscientist Chelsea Kaplan of the Chronic Pain and Fatigue Research Center at the University of Michigan in Ann Arbor.

The study was done on only four people, three with pain from a stroke and one with phantom limb pain after a leg amputation. “We would need to know if these findings can generalize to other patients and pain conditions,” Kaplan says.

If brain activity patterns end up being common across people with chronic pain, they might one day be used to measure pain in people who can’t communicate, Martucci says. That includes people in nonresponsive states such as those with locked-in syndrome (SN: 7/28/15).

Yet the goal of identifying reliable markers of chronic pain is not necessarily to establish whether a person is in pain, or serve as a yes-no diagnostic test, study coauthor Prasad Shirvalkar, a neurologist at UCSF, said in a May 18 news briefing. Instead, it’s to guide treatment. Shirvalkar and his colleagues are now conducting a clinical trial that involves stimulating peoples’ brains to treat chronic pain. “I think of [the biomarker] as one tool to actually help treat a patient, to actually make them feel more seen.”

22 May. 2023

Saturn’s rings might have formed while trilobites scuttled about on Earth. Space dust has been accumulating on the icy halos for no more than 400 million years, researchers report in the May 12 Science Advances.

The 4.5-billion-year-old planet appears to have acquired its iconic ornamentation relatively recently, says physicist Sascha Kempf of the University of Colorado Boulder. “We’re quite lucky to see a ring in the first place.”

The rings of Saturn are made of countless icy particles, which become covered with dust as tiny meteoroids strike them. These dustings darken the rings’ complexion, like mud sullies snow on roads in winter.

This cosmic staining was key to the new analysis, as was the now-defunct Cassini spacecraft’s Cosmic Dust Analyzer. From 2004 to 2017, the instrument caught dust-sized micrometeoroids moving around Saturn, measuring their velocity, mass, charge and composition.

Kempf and colleagues identified about 160 particles — out of millions — that could have hailed from beyond the Saturn system. The researchers estimated the rate at which the incoming dust accumulates on Saturn’s rings, and calculated how long it would have taken to darken the rings to their observed color. The planet’s hoops might have materialized more than 100 million years after trilobites — mysterious, extinct invertebrates — appeared on Earth, the team found (SN: 8/30/19).

The age of the rings has been debated for decades (SN: 10/20/16). Even after the new study, there’s still disagreement.

If the rings are somehow losing dust over time, they could be ancient, says planetary scientist Aurélien Crida of Université Côte d’Azur in Nice, France, who was not involved in the study. “Possibly as old as Saturn.”

It seems clear that the rings have been exposed to micrometeoroid impacts for at least a hundred million years, Crida says. But simulations of the rings’ formation from the gravitational shredding of an early moon suggest their size is consistent with an age of billions of years, he says. And researchers have reported silicate grains falling from the rings into Saturn’s atmosphere (SN: 10/4/18). Some unidentified process might be cleaning the rings of the micrometeoroid dust, making them appear younger than they are, Crida says.

Alternatively, the previously reported falling dust might come from meteoroid impacts that shatter ring ice, Kempf says.

Experiments that smash micrometeoroids into ice particles could help resolve the discrepancy, Crida says. For now, the debate over the age of the rings lives on.

21 May. 2023

Heating an insecticide can give it new life.

Microwaving the insecticide deltamethrin rearranges its crystal structure but doesn’t change its chemical composition. The rearrangement renews deltamethrin’s ability to kill mosquitoes that have become resistant to the insecticide, researchers report April 21 in Malaria Journal.

The researchers didn’t set out to revive insecticides, says Bart Kahr, a crystallographer at New York University. He and colleagues had been working on crystal growth experiments. “And it turns out that a very good crystal for the experiment that we wanted to do was DDT, the very old, notorious insecticide from the last century.” The researchers realized that DDT has two crystal forms, one of which works better than the other.

They then started experimenting with deltamethrin, an insecticide that is commonly used against mosquitoes that can carry malaria. The chemical is often incorporated into bed nets or sprayed on walls or other surfaces in homes. Mosquitoes absorb the insecticide when they come in contact with it. Kahr and colleagues previously discovered that heating deltamethrin changed its crystal structure, which let it work faster (SN: 10/19/20).

Altering the arrangement of crystals is a tried-and-true way of giving drugs new and different properties, Kahr says. But no one had thought to rearrange insecticide crystals to give them new life, he says. “We just were surprised at how relevant it really was, and a little surprised that nobody has looked at this before,” he says. “Different communities of scientists just have different urgencies. And sometimes when you come from the outside, you look at things from a completely different way.”

Kahr’s team heated a chalk formulation of deltamethrin called D-Fense Dust either in an oven or in a microwave. In the oven, the researchers could precisely control the temperature, he says. “But just for kicks, we said because this deltamethrin is a consumer product, what if you just pop it in the microwave for five minutes? Does that achieve the same thing as heating it to a prescribed temperature in the oven?” The microwave worked just as well, but Kahr cautions that people shouldn’t use the same microwave for heating food and insecticides.

Two microscope images of deltamethrin's crystal structure. The image on the left is the insecticide's typical crystal structure and the image on the right is of the crystal structure heated.
Popping deltamethrin in the microwave for a few minutes rearranges the insecticide’s typical crystal structure (left). Tests of heated deltamethrin crystals (right) showed that they are effective against mosquitoes resistant to the insecticide’s usual form.Jingxiang Yang

Previously, the researchers had tested the heated deltamethrin crystals on mosquitoes that were already sensitive to the insecticide. In the new study, the scientists teamed up with entomologists to test the heated crystals on five strains of Anopheles mosquitoes from West Africa that are resistant to deltamethrin. In all cases, the rearranged crystals killed the resistant mosquitoes.

That’s important because insecticide resistance is a growing problem and is impairing the ability to control mosquito populations to tamp down malaria spread, says Janet Hemingway, a geneticist at the Liverpool School of Tropical Medicine in England who was not involved in the new study. “We’re now at the point where almost nowhere in Africa is fully susceptible.”

It is encouraging that heated insecticide killed highly resistant mosquitoes, says Hemingway, who directs the Infection Innovation Consortium, a public-private effort to find new ways to combat infectious diseases. But, she says, “this is not something we can take and use that tomorrow.”

For instance, insecticide-treated bed nets are made by mixing deltamethrin with fibers before yarn is extruded. The insecticide migrates to the outside of the yarn and forms crystals. Depending on the manufacturer, “the crystal structures that end up on the surfaces of those bed nets can be quite different,” Hemingway says.

It’s not certain that the heat-treated deltamethrin would retain its more potent crystal structure through the net-making process. And you couldn’t just pop bed nets in the microwave to rearrange the deltamethrin crystals, she says. “You’d need some pretty big microwaves given these things come in shipping containers.”

Kahr’s team is working on incorporating the heat-treated crystal into nets. Liquid sprays are out since the rearranged crystals don’t retain their structure when mixed into water. People could spray the heated chalk instead, but few people would probably want chalky walls, Kahr says. “There are all kinds of social and cultural things that you could propose from a scientific perspective that wouldn’t be welcomed by a community of homeowners.”

19 May. 2023

The world goes dark for about one-fifth of a second every time you blink, a fraction of an instant that’s hardly noticeable to most people. But for a Formula One race car driver traveling up to 354 kilometers per hour, that one-fifth means almost 20 meters of lost vision.

Considering how often people blink (up to 30 times every minute), a driver could lose as much as 595 meters — over a third of a mile — worth of visual information per minute due to blinking.

People are often thought to blink at random intervals, but researchers found that wasn’t the case for three Formula drivers. Instead, the drivers tended to blink at the same parts of the course during each lap, cognitive neuroscientist Ryota Nishizono and colleagues report in the May 19 iScience.

Nishizono, of NTT Communication Science Laboratories in Atsugi, Japan, was inspired to study how humans process information during physical activity by his past as a professional racing cyclist.

He was surprised to find almost no literature on blinking behavior in active humans even though under extreme conditions like motor racing or cycling, “a slight mistake could lead to life-threatening danger,” Nishizono says. So he partnered with a Japanese Formula car racing team to examine how humans blink during high-speed driving.

Nishizono and colleagues mounted eye trackers on the helmets of three drivers and had them drive three Formula circuits — Fuji, Suzuka and Sugo — for a total of 304 laps.

Where the drivers blinked was surprisingly predictable, the team found. The drivers had a shared pattern of blinking that had a strong connection with acceleration, such that drivers tended not to blink while changing speed or direction — like while on a curve in the track — but did blink while on relatively safer straightaways.

The finding highlights the trade-off between keeping our eyes moist and not losing vision during crucial tasks, says Jonathan Matthis, a neuroscientist at Northeastern University in Boston who studies human movement and was not involved in the research. “We think of blinking as this nothing behavior,” he says, “but it’s not just wiping the eyes. Blinking is a part of our visual system.”

Nishizono next wants to explore what processes in the brain allow or inhibit blinking in a given moment, he says, and is also interested in how blinking behavior varies among the general population.

19 May. 2023

Being able to buy birth control pills off the shelf took a big step forward on May 10. Two advisory committees to the U.S. Food and Drug Administration voted unanimously to make a birth control pill available without a prescription.

The pill, called Opill and known by the generic name norgestrel, is a progestin-only pill. That’s in contrast to combined oral contraceptive pills, which contain progestin—or another form of progesterone — along with a form of estrogen (SN: 4/13/23). Progesterone and estrogen are two of the hormones that regulate the menstrual cycle.

Opill gained FDA approval for prescription use in the United States in 1973, under a different brand name. The advisory committees that recently met were tasked with considering a switch from prescription to over-the-counter status, which involves reviewing data that the drug can be used safely and effectively without the oversight of a physician.

The FDA committees — one with expertise on non-prescription drugs, the other with obstetric and gynecological drugs — endorsed the switch, and they are not alone. Medical organizations including the American College of Obstetricians and Gynecologists, the American Medical Association and the American Academy of Family Physicians are also in favor of an over-the-counter birth control pill. The FDA is expected to announce a decision on the recommendation this summer.

If Opill gets the over-the-counter nod, it would become the most effective birth control method on store shelves, surpassing existing options like condoms and sponges. It would also remove barriers that can make getting this birth control option challenging for many people.

The possibility that a birth control pill could become more easily available comes as the United States faces a maternal mortality crisisabortion bans and possible restrictions on an FDA-approved abortion medication (SN: 3/16/23; SN: 6/24/22; SN: 5/18/23). Science News talked with two sexual and reproductive health equity researchers about the impact of over-the-counter access to the pill on reproductive health and autonomy. The interviews were edited for length and clarity.

SN: What barriers do adults and adolescents face in terms of access to different birth control methods?

Rachel Logan, University of California, San Francisco: I think it’s the same barriers for both groups, although I think adolescents face more. It is transportation to health care appointments. [There are] barriers within care, such as some providers requiring a pelvic examination or a full gynecological exam before providing or prescribing contraceptive methods. [It is] a lack of insurance coverage. Unfortunately in this country, because we don’t have federally mandated, comprehensive sex ed, some people just may not know about all of the contraceptive methods that exist.

There continues to be the stigma associated with needing contraception and who uses contraception that is very patriarchal and really demeaning to people, like it says something about you if you have to use these methods, as opposed to [contraception being] an essential tool in your reproductive health journey. Another area that I don’t think is talked enough about is contraceptive coercion — that could be from a parent, a partner or a health care provider — where your options to use the method of your choice are limited for whatever reason.

SN: What could it mean for adults and adolescents to have over-the-counter access to hormonal birth control, especially considering the maternal mortality crisis and abortion bans?

Anu Manchikanti Gómez of the University of California, Berkeley: Providing people the opportunity to be unpregnant is always important, but more important than ever because of these additional crises. Abortion bans have many effects, obviously, on people’s ability to access abortion. But [bans are also] having a chilling effect on health care providers in some states. Maybe they are leaving those states where abortion is banned, or not coming [to those states] in the first place. Those are generally the same providers who might be doing contraceptive counseling or providing pap smears or prenatal care, [so] there can be less access to this care. Birth control can’t solve those issues, but there may be ways that more access is going to be particularly helpful when access is being lost in other ways.

Logan: It feels like we’re in a very critical moment where reproductive autonomy is definitely under threat. So this could mean extending options to people who otherwise may not have an option or a way to obtain a method of birth control that works for them. Being able to walk into a store and pick something off of the shelf that you can use and is very safe and effective is life changing.

SN: What do we know about the historical impact of prescription birth control?

Gómez: The availability of hormonal birth control has been transformative for, historically, cis gender women’s participation in the world, in the workforce, in their ability to engage in education. Being able to control your fertility is such an important part about being able to control your destiny. There are many things that can affect our ability to live the lives that we want, but if you are a person who can become pregnant, [it’s] really important to have the option of deciding if, when and how you want to become pregnant or remain pregnant.

SN: When choosing a birth control method, what does it mean to take a person-centered contraceptive care approach?

Gómez: A person-centered approach, if we’re talking about contraceptive access, means … actually support[ing] the person in making the decision that’s best for them versus what someone else thinks they should be doing. There’s a long history of birth control abuse and coercion in the United States, from forced sterilization to aggressive promotion of certain methods toward Black communities and people who are poor. Even though there are different levels of effectiveness of different types of methods, that doesn’t make one more medically appropriate.

For some people, they don’t like something that they can’t stop using without going to see a health care provider [such as an implant or other long-acting reversible contraception]. You may feel that you’re losing bodily autonomy through using a method that you can’t stop using on your own. That’s a very real concern for some people, and it’s definitely grounded in some of the historical abuses and racism and ongoing experiences of low-quality care that some people, too many people, experience.

Logan: [A person-centered approach] is being OK with people saying, “no,  I don’t want to use that method,” and saying, “that’s fine,” as opposed to [providers] feeling like it’s their job to convince people to get on a method or to use a particular method. [It’s] showing people that you care about them using what feels right and best for them. We’re aligning people’s preferences with methods that are available.

SN: Does the possible over-the-counter availability of hormonal birth control assist with this approach?

Logan: Yes. It gives people the power that they need without these constraints that are really only hurdles. This is in no way to replace routine preventative care. It is to reduce barriers to methods that we know are safe and effective that people can use independently. I think the health care system is already very strained. Is it a good thing that we’re moving some services that we know to be safe and effective outside of the health care system? I would say yes.

Gómez: [Easier access] can make a huge difference for people. Being able to start using [a birth control pill] without seeing a provider, that removes many layers of barriers. All of those can reduce people’s ability to use it at all or to use it continuously. Not everyone wants to use the pill, [but for those who do] having over-the-counter access is really going to help people.

19 May. 2023

Many writers grouse when an editor makes a change in a story, but the consequences of changing a single word usually aren’t that dire.

Not so with genetic instructions for making proteins. Even a small change can prevent a protein from doing its job properly, with possibly deadly consequences. Only occasionally is a change beneficial. It seems wisest to preserve genetic instructions as they are written. Unless you’re an octopus.

Octopuses are like aliens living among us — they do a lot of things differently from land animals, or even other sea creatures. Their flexible tentacles taste what they touch and have minds of their own. Octopuses’ eyes are color-blind, but their skin can detect light on its own (SN: 6/27/15, p. 10). They are masters of disguise, changing color and skin textures to blend into their surroundings or scare off rivals. And to a greater extent than most creatures, octopuses squirt the molecular equivalent of red ink over their genetic instructions with astounding abandon, like a copy editor run amok.

These edits modify RNA, the molecule used to translate information from the genetic blueprint stored in DNA, while leaving the DNA unaltered.

Scientists don’t yet know for sure why octopuses, and other shell-less cephalopods including squid and cuttlefish, are such prolific editors. Researchers are debating whether this form of genetic editing gave cephalopods an evolutionary leg (or tentacle) up or whether the editing is just a sometimes useful accident. Scientists are also probing what consequences the RNA alterations may have under various conditions. Some evidence suggests editing may give cephalopods some of their smarts but could come at the cost of holding back evolution in their DNA (SN: 4/29/17, p. 6).

“These animals are just magical,” says Caroline Albertin, a comparative developmental biologist at the Marine Biological Laboratory in Woods Hole, Mass. “They have all sorts of different solutions to living in the world they come from.” RNA editing may help give the creatures vast numbers of solutions for problems they may face.

Unlike other animals with bilateral symmetry, octopuses don’t crawl in a predetermined direction. Videos of octopuses crawling show they can move in any direction relative to their body, and they change crawling direction independently of turning their bodies. In the clip, the green arrow marks the orientation of the octopus’ body and a blue arrow marks the direction it is crawling.

How cephalopods modify their RNA

Molecular biology’s central dogma holds that instructions for building an organism are contained in DNA. Cells copy those instructions into messenger RNAs, or mRNAs. Then, cellular machinery called ribosomes read the mRNAs to build proteins by stringing amino acids together. Most of the time, the protein’s composition conforms to the DNA template for the protein’s sequence of amino acids.

But RNA editing can cause divergences from the DNA instructions, creating some proteins that have different amino acids than specified by the DNA.

Editing chemically modifies one of RNA’s four building blocks, or bases. Those bases are often referred to by the first letters of their names: A, C, G and U, for adenine, cytosine, guanine and uracil (RNA’s version of the DNA base thymine). In an RNA molecule, the bases are linked to sugars; the adenine-sugar unit, for instance, is referred to as adenosine.

There are many ways to edit RNA letters. Cephalopods excel at a type of editing known as adenosine to inosine, or A-to-I, editing. This happens when an enzyme called ADAR2 strips a nitrogen and two hydrogen atoms off adenosine (the A). That chemical peel turns adenosine into inosine (I).

Ribosomes read inosine as guanine instead of adenine. Sometimes that switch has no effect on the resulting protein’s chain of amino acids. But in some cases, having a G where an A should be results in a different amino acid being inserted into the protein. Such protein-altering RNA editing is called RNA recoding.

Soft-bodied cephalopods have embraced RNA recoding with all of their arms while even closely related species are more tentative about accepting rewrites, Albertin says. “Other mollusks don’t seem to do it” to the same extent.

RNA editing isn’t limited to creatures of the deep. Almost every multicellular organism has one or more RNA editing enzymes called ADAR enzymes, short for “adenosine deaminase that acts on RNA,” says Joshua Rosenthal, a molecular neurobiologist also at the Marine Biological Laboratory.

Cephalopods have two ADAR enzymes. Humans have versions of them, too. “In our brains, we edit a ton of RNA. We do it a lot,” Rosenthal says. Over the last decade, scientists have discovered millions of places in human RNAs where editing occurs.

But those edits rarely change the amino acids in a protein. For instance, Eli Eisenberg of Tel Aviv University and colleagues identified more than 4.6 million editing sites in human RNAs. Of those, only 1,517 recode proteins, the researchers reported last year in Nature Communications. Of those recoding sites, up to 835 are shared with other mammals, suggesting that evolutionary forces preserved editing at those locations.

Cephalopods take RNA recoding to a whole new level, Albertin says. Longfin squid (Doryteuthis pealeii) have 57,108 recoding sites, Rosenthal, Eisenberg and colleagues reported in 2015 in eLife. Since then, the researchers have examined multiple species of octopus, squid and cuttlefish, each time finding tens of thousands of recoding sites.

Soft-bodied, or coleoid, cephalopods may have more opportunities for editing than other animals because of where at least one of the ADAR enzymes, ADAR2, is located in the cell. Most animals edit RNAs in the nucleus — the compartment where DNA is stored and copied into RNA — before sending the messages out to meet up with ribosomes. But cephalopods also have the enzymes in the cytoplasm, the cells’ jellylike guts, Rosenthal and colleagues discovered (SN: 4/25/20, p. 10).

Having editing enzymes in two locales doesn’t fully explain why cephalopods’ RNA recoding so far outstrips that of humans and other animals. Nor does it explain the patterns of editing scientists have uncovered.

RNA editing may give cephalopods flexibility

Editing isn’t an all-or-nothing proposition. Rarely are all copies of an RNA in a cell edited. It’s much more common for some percentage of RNAs to be edited while the rest retain their original information. The percentage, or frequency, of editing can vary widely from RNA to RNA or between cells or tissues, and may depend on water temperature or other conditions. In longfin squid, most RNA editing sites were edited 2 percent or less of the time, Albertin and colleagues reported last year in Nature Communications. But the researchers also found more than 205,000 sites that were edited 25 percent of the time or more.

In most of a cephalopod’s body, RNA editing doesn’t often affect the makeup of proteins. But in the nervous system, it’s a different story. In longfin squids’ nervous systems, 70 percent of edits in protein-producing RNAs recode proteins. And RNAs in the nervous system of the California two-spot octopus (Octopus bimaculoides) are recoded three to six times as often as in other organs or tissues.

longfin squid
The longfin squid recodes RNA at more than 50,000 locations. RNA recoding might help the squid respond more flexibly to its environment, but whether recoding has evolutionary value is not yet clear.ELAINE BEARER

Some mRNAs have multiple edit sites that alter amino acids in the proteins the mRNAs encode. In the longfin squid’s nervous system, for instance, 27 percent of mRNAs have three or more recoding sites. Some contain 10 or more such sites. Combinations of those editing sites could result in multiple versions of a protein being made in a cell.

Having a wide selection of proteins may give cephalopods “more flexibility in responding to the environment,” Albertin says, “or give you a variety of solutions to the problem in front of you.” In the nervous system, RNA editing might contribute to flexibility in thinking, which could help explain why octopuses can unlock cages or use tools, some researchers think. Editing could be an easy way to create one or more versions of a protein in the nervous system and different ones in the rest of the body, Albertin says.

When humans and other vertebrates have different versions of a protein, it often comes from having multiple copies of a gene. Doubling, tripling or quadrupling copies of a gene “results in a whole genetic playground to allow genes to go off and do different functions,” Albertin says. But cephalopods tend not to duplicate genes. Instead, their innovations come from editing.

And there is a lot of room for innovation. In squid, mRNAs for building the alpha-spectrin protein have 242 recoding sites. All the combinations of edited and unedited sites theoretically could create up to 7 x 1072 forms of the protein, Rosenthal and Eisenberg report in this year’s issue of Annual Review of Animal Biosciences. “To put this number in perspective,” the researchers wrote, “suffice it to say that it dwarfs the number of all alpha-spectrin molecules (or, for that matter, all protein molecules) synthesized in all cells of all the squids that have ever lived on our planet since the dawn of time.”

That incredible level of complexity would be possible only if every site were independent, says Kavita Rangan, a molecular biologist at the University of California, San Diego. Rangan has been studying RNA recoding in California market squid (Doryteuthis opalescens) and in longfin squid. Water temperature triggers the squid to recode motor proteins called kinesins that move cargo inside cells.

In longfin squid, the mRNA that produces kinesin-1 has 14 recoding sites, Rangan has found. She examined mRNAs from the optic lobe — the part of the brain that processes visual information — and from the stellate ganglion, a collection of nerves involved in generating the muscle contractions that produce jets of water to propel the squid.

Each tissue made several versions of the protein. But certain sites tended to be edited together, Rangan and Samara Reck-Peterson, also of UC San Diego, reported last September in a preprint posted online at Their data suggest that editing of some sites is coordinated and “very strongly rejects the idea that editing is independent,” Rangan says. “The frequency of the combos that we see don’t match if every site was edited independently.”

Yoking editing sites may prevent squid and other cephalopods from reaching the pinnacles of complexity that they’re theoretically capable of. Still, RNA editing provides cephalopods a way to try out many versions of a protein without getting locked into a permanent change in DNA, Rangan says.

That lack of commitment puzzles Jianzhi Zhang, an evolutionary geneticist at the University of Michigan in Ann Arbor. “It doesn’t make sense to me,” he says. “If you want a particular amino acid in a protein, you should change the DNA. Why do you change the RNA?”

Is there evolutionary value to RNA editing?

Perhaps RNA editing provides some evolutionary advantage. To test that idea, Zhang and then–graduate student Daohan Jiang compared “synonymous” sites, where edits do not change amino acids, with “nonsynonymous” sites where recoding happens. Since synonymous edits don’t change amino acids, the researchers considered those edits to be neutral as far as evolution is concerned. In humans, recoding, or nonsynonymous editing, happens at fewer sites than synonymous editing, and the percentage of RNA molecules that are edited is lower than at synonymous sites.

“If we assume synonymous editing is just like noise that happens in the cell, and nonsynonymous editing is less frequent and [at a] lower level, that suggests nonsynonymous editing is actually harmful,” Zhang says. Even though recoding in cephalopods happens much more frequently than for humans, in most cases, recoding is not advantageous, or adaptive, for cephalopods, the researchers argued in 2019 in Nature Communications.

There are a few shared sites where octopuses, squid and cuttlefish all recode their RNAs, the researchers found, suggesting the recoding is useful in those instances. But this is a small fraction of editing sites. A few other sites that are edited in one species of cephalopod but not others were also adaptive, Zhang and Jiang found.

If it’s not all that helpful, why have cephalopods persisted with RNA recoding for hundreds of millions of years? RNA editing may stick around not because it is adaptive, but because it is addictive, Zhang says.

He and Jiang proposed a harm-permitting model (that is, a situation that permits harmful changes to DNA). Imagine, he says, a situation in which a G (guanine) in an organism’s DNA gets mutated to an A (adenine). If that mutation leads to a harmful amino acid change in a protein, natural selection should weed out individuals that carry that mutation. But if, by chance, the organism has RNA editing, the mistake in the DNA might be corrected by editing RNA, essentially changing the A back to G. If the protein is essential for life, then the RNA would have to be edited at high levels so that nearly every copy is corrected.

When that happens, “You’re locked into the system,” Zhang says. Now the organism is dependent on RNA editing machinery. “It cannot be lost, because you will require the A to be edited back to G for survival, so the editing will be kept at high levels.… In the beginning you really didn’t need it, but after you got it, you became addicted.”

Zhang argues that that sort of editing is neutral, not adaptive. But other research suggests RNA editing can be adaptive.

RNA editing may work as a transition phase, letting organisms try out a switch from adenine to guanine without making a permanent change in their DNA. Over the course of evolution, sites where adenines are recoded in RNA in one cephalopod species are more likely than unedited adenines to be replaced with guanine in the DNA of one or more related species, researchers reported in 2020 in PeerJ. And for heavily edited sites, evolution across cephalopods seems to favor a transition from A to G in DNA (rather than to cytosine or thymine, the other two DNA building blocks). That favors the idea that editing can be adaptive.

Other recent work by Rosenthal and colleagues, which examined A-to-G replacements in different species, suggests that having an editable A is an evolutionary boon over an uneditable A or a hardwired G.

There are a lot of open questions

Evidence for and against RNA recoding’s evolutionary value has come mainly from examining the total genetic makeup, or genomes, of various cephalopod species. But scientists would like to directly test whether recoded RNAs have an effect on cephalopod biology. Doing that will require some new tools and creative thinking.

Rangan tested synthetic versions of squid motor proteins and found that two edited versions that squid make in the cold moved slower but traveled farther along protein tracks called microtubules than unedited proteins did. But that’s in artificial laboratory conditions on microscope slides. To understand what is happening in cells, Rangan says, she would like to be able to grow squid cells in lab dishes. Right now, she has to take tissue directly from the squid and can only get snapshots of what is happening. Lab-grown cells might allow her to follow what happens over time.

Zhang says he is testing his harm-permitting hypothesis by getting yeast hooked on RNA editing. Baker’s yeast (Saccharomyces cerevisiae) doesn’t have ADAR enzymes. But Zhang engineered a strain of the yeast to carry a human version of the enzyme. The ADAR enzymes make the yeast sick and grow slowly, he says. To speed up the experiment, the strain he is using has a higher-than-normal mutation rate, and may build up G-to-A mutations. But if RNA editing can correct those mutations, the ADAR-carrying yeast may grow better than ones that don’t have the enzyme. And after many generations, the yeast may become addicted to editing, Zhang predicts.

Albertin, Rosenthal and colleagues have developed ways to change the genes of squid with the gene editor CRISPR/Cas9. The team created an albino squid by using CRISPR/Cas9 to knock out, or disable, a gene that produces pigment. The researchers may be able to change editing sites in DNA or in RNA and test their function, Albertin says.

This science is still in its early stages, and the story may lead somewhere unexpected. Still, with cephalopods’ skillful editing, it’s bound to be a good read.