Science – Page 12

Clinical trial of a technique that could give everyone the best antibodies

antibodies, Biology, DNA, electroporation, medicine, plasmid, Policy, Science / Paul Patrick / October 24, 2025

If we ID the DNA for a great antibody, anyone can now make it.

One of the things that emerging diseases, including the COVID and Zika pandemics, have taught us is that it’s tough to keep up with infectious diseases in the modern world. Things like air travel can allow a virus to spread faster than our ability to develop therapies. But that doesn’t mean biotech has stood still; companies have been developing technologies that could allow us to rapidly respond to future threats.

There are a lot of ideas out there. But this week saw some early clinical trial results of one technique that could be useful for a range of infectious diseases. We’ll go over the results as a way to illustrate the sort of thinking that’s going on, along with the technologies we have available to pursue the resulting ideas.

The best antibodies

Any emerging disease leaves a mass of antibodies in its wake—those made by people in response to infections and vaccines, those made by lab animals we use to study the infectious agent, and so on. Some of these only have a weak affinity for the disease-causing agent, but some of them turn out to be what are called “broadly neutralizing.” These stick with high affinity not only to the original pathogen, but most or all of its variants, and possibly some related viruses.

Once an antibody latches on to a pathogen, broadly neutralizing antibodies inactivate it (as their name implies). This is typically because these antibodies bind to a site that’s necessary for a protein’s function. For example, broadly neutralizing antibodies to HIV bind to the proteins that help this virus enter immune cells.

Unfortunately, not everyone develops broadly neutralizing antibodies, and certainly doesn’t do so in time to prevent infections. And we haven’t figured out a way of designing vaccinations that ensure their generation. So we’re often found ourselves stuck with knowing what antibodies we’d like to see people making while having no way of ensuring that they do.

One of the options we’ve developed is to just mass-produce broadly neutralizing antibodies and inject them into people. This has been approved for use against Ebola and provided an early treatment during the COVID pandemic. This approach has some practical limitations, though. For starters, the antibodies have a finite life span in the bloodstream, so injections may need to be repeated. In addition, making and purifying enough antibodies in bulk isn’t the easiest thing in the world, and they generally need to be kept refrigerated during the distribution, limiting the areas where they can be used.

So, a number of companies have been looking at an alternative: getting people to make their own. This could potentially lead to longer-lived protection, even ensuring the antibodies are present to block future infections if the DNA survives long enough.

Genes and volts

Once you identify cells that produce broadly neutralizing antibodies, it’s relatively simple to clone those genes and put them into a chunk of DNA that will ensure that they’ll be produced by any human cell. If we could get that DNA into a person’s cells, broadly neutralizing antibodies are the result. And a number of approaches have been tried to handle that “if.” Most of them have inserted the genes needed to make the antibodies into a harmless, non-infectious virus, and then injected that virus into volunteers. Unfortunately, these viruses have tended to set off a separate immune response, which causes more significant side effects and may limit how often this approach can be used.

This brings us to the technique being used here. In this case, the researchers placed the antibody genes in a circular loop of DNA called a plasmid. This is enough to ensure that the DNA doesn’t get digested immediately and to get the antibody genes made into proteins. But it does nothing to help get the DNA inside of cells.

The research team, a mixture of people from a biotech company and academic labs, used a commercial injection setup that mixes the injection of the DNA with short pulses of electricity. The electricity disrupts the cell membrane, allowing the plasmid DNA to make it inside cells. Based on animal testing, doing this in muscle cells is enough to turn the muscles into factories producing lots of broadly neutralizing antibodies.

The new study was meant to test the safety of doing that in humans. The team recruited 44 participants, testing various doses of two antibody-producing plasmids and injection schedules. All but four of the subjects completed the study; three of those who dropped out had all been testing a routine with the electric pulses happening very quickly, which turned out to be unpleasant. Fortunately, it didn’t seem to make any difference to the production of antibodies.

While there were a lot of adverse reactions, most of these were associated with the injection itself: muscle pain at the site, a scab forming afterward, and a reddening of the skin. The worst problem appeared to be a single case of moderate muscle pain that persisted for a couple of days.

In all but one volunteer, the injection resulted in stable production of the two antibodies for at least 72 weeks following the injection; the single exception only made one of the two. That’s “at least” 72 weeks because that’s when they stopped testing—there was no indication that levels were dropping at this point. Injecting more DNA led to more variability in the amount of antibody produced, but that amount quickly maxed out. More total injections also boosted the level of antibody production. But even the minimal procedure—two injections of the lowest concentration tested—resulted in significant and stable antibodies.

And, as expected, these antibodies blocked the virus they were directed against: SARS-CoV-2.

The caveats

This approach seems to work—we can seemingly get anybody to make broadly neutralizing antibodies for months at a time. What’s the hitch? For starters, this isn’t necessarily great for a rapidly emerging pandemic. It takes a while to identify broadly neutralizing antibodies after a pathogen is identified. And, while it’s simple to ship DNA around the world to where it will be needed, injection setups that also produce the small electric pulses are not exactly standard equipment even in industrialized countries, much less the Global South.

Then there’s the issue of whether this really is a longer-term fix. Widespread use of broadly neutralizing antibodies will create a strong selective pressure for the evolution of variants that the antibody can no longer bind to. That may not always be a problem—broadly neutralizing antibodies generally bind to parts of proteins that are absolutely essential for the proteins’ function, and so it may not be possible to change those while maintaining the function. But that’s unlikely to always be the case.

In the end, however, social acceptance may end up being the biggest problem. People had an utter freakout over unfounded conspiracies that the RNA of COVID vaccines would somehow lead to permanent genetic changes. Presumably, having DNA that’s stable for months would be even harder for some segments of the public to swallow.

Nature Medicine, 2025. DOI: 10.1038/s41591-025-03969-0 (About DOIs).

John is Ars Technica’s science editor. He has a Bachelor of Arts in Biochemistry from Columbia University, and a Ph.D. in Molecular and Cell Biology from the University of California, Berkeley. When physically separated from his keyboard, he tends to seek out a bicycle, or a scenic location for communing with his hiking boots.

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Bats eat the birds they pluck from the sky while on the wing

bats, Biology, birds, Ecology, hunting, Science / Kris Guyer / October 24, 2025

There are three species of bats that eat birds. We know that because we have found feathers and other avian remains in their feces. What we didn’t know was how exactly they hunt birds, which are quite a bit heavier, faster, and stronger than the insects bats usually dine on.

To find out, Elena Tena, a biologist at Doñana Biological Station in Seville, Spain, and her colleagues attached ultra-light sensors to Nyctalus Iasiopterus, the largest bats in Europe. What they found was jaw-droppingly brutal.

Inconspicuous interceptors

Nyctalus Iasiopterus, otherwise known as greater noctule bats, have a wingspan of about 45 centimeters. They have reddish-brown or chestnut fur with a slightly paler underside, and usually weigh around 40 to 60 grams. Despite that minimal weight, they are the largest of the three bat species known to eat birds, so the key challenge in getting a glimpse into the way they hunt was finding sensors light enough to not impede the bats’ flight.

Cameras, which are the usual go-to sensor, were out of the question. “Bats hunt at night, so you’d need night vision cameras, which together with batteries are too heavy for a bat to carry. Our sensors had to weigh below 10 percent of the weight of the bat—four to six grams,” Tena explained.

Tena and her team explored several alternative approaches throughout the last decade, including watching the bats from the ground or using military-grade radars. But even then, catching the hunting bats red-handed remained impossible.

In recent years, the technology and miniaturization finally caught up with Tena’s needs, and the team found the right sensors for the job and attached them to 14 greater noctule bats over the course of two years. The tags used in the study weighed around four grams, could run for several hours, and registered sound, altitude, and acceleration. This gave Tena and her colleagues a detailed picture of the bats’ behavior in the night sky. The recordings included both ambient environmental sounds and the ultra-frequency bursts bats use for echolocation. Combining altitude with accelerometer readouts enabled scientists to trace the bats’ movements through all their fast-paced turns, dives, and maneuvers.

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Dinosaurs may have flourished right up to when the asteroid hit

asteroid, Biology, dinosaurs, evolution, Impact, paleontology, Science / Kris Guyer / October 23, 2025

That seemingly changes as of now, with new argon dating of strata from the Naashoibito Member in the San Juan Basin of present-day New Mexico. Many dinosaur fossils have been obtained from this region, and we know the site differs from the sort of ecosystem found at Hell Creek. But it was previously thought to date back closer to a million years before the mass extinction. The new dates, plus the alignment of magnetic field reversals, tell us that the ecosystem was a contemporary of the one in Hell Creek, and dates to the last few hundred thousand years prior to the mass extinction.

Diverse ecosystems

The fossils at Naashoibito have revealed an ecosystem we now label the “Alamo Wash local fauna.” And they’re fairly distinct from the ones found in Wyoming, despite being just 1,500 kilometers further south. Analyzing the species present using ecological measures, the researchers found that dinosaurs formed two “bioprovinces” in the late Cretaceous—essentially, there were distinct ecosystems present in the northern and southern areas.

This doesn’t seem to be an artifact of the sites, as mammalian fossils seem to reflect a single community across both areas near the mass extinction, but had distinct ecologies both earlier and after. The researchers propose that temperature differences were the key drivers of the distinction, something that may have had less of an impact on mammals, which are generally better at controlling their own temperatures.

Overall, the researchers conclude that, rather than being dominated by a small number of major species, “dinosaurs were thriving in New Mexico until the end of the Cretaceous.”

While this speaks directly to the idea that limited diversity may have primed the dinosaurs for extinction, it also may have implications for the impact of the contemporaneous eruptions in the Deccan Traps. If these were having a major global impact, then it’s a bit unlikely that dinosaurs would be thriving anywhere.

Even with the new data, however, our picture is still limited to the ecosystems present on the North American continent. We do have fossils from elsewhere, but they’re not exactly dated. There are some indications of dinosaurs in the late Cretaceous in Europe and South America, but we don’t have a clear picture of the ecosystems in which they were found. So, while these findings help clarify the diversity of dinosaurs in the time leading up to their extinction, there’s still a lot left to learn.

Science, 2025. DOI: 10.1126/science.adw3282 (About DOIs).

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An NIH director joins MAHA, gets replaced by JD Vance’s close friend

cancer, cellphones, fluoride, health, NIEHS, NIH, NTP, robert f kennedy jr, Science, trump administration / Paul Patrick / October 23, 2025

The director of a federal health institute that has arguably produced two of the most controversial government studies in recent years has accepted a new federal role to advance the goals of the Make America Healthy Again movement. Meanwhile, the person replacing him as director is a close friend of Vice President JD Vance and was installed in a process that experts describe as completely outside standard hiring practices.

The series of events—revealed in an email to staff last week from the National Institutes of Health Director Jay Bhattacharya—is only exacerbating the spiraling fears that science is being deeply corrupted by politics under the Trump administration.

Richard Woychik, a molecular geneticist, is the outgoing director of the NIH’s National Institute of Environmental Health Sciences (NIEHS), which is located in Research Triangle Park, North Carolina. He has been director since 2020 and was recently appointed to a second five-year term, according to Science magazine. Woychik was hired at the institute in 2010, when he joined as deputy director, and was appointed acting director in 2019.

As the director of NIEHS, Woychik was also the director of the National Toxicology Program (NTP). This is an interagency program that has produced two highly controversial scientific reports during Woychik’s time in NIEHS’s upper leadership. One, initially released in 2016, claimed that cellphone radiation causes cancer based on findings from rats, though only male rats. The final reports were published in 2018. Another controversial study, finalized this year, suggested that high levels of fluoride lower the IQ of children. Both the cellphone radiation and fluoride studies have been roundly criticized for flaws in their methodology and analysis, and the scientific community has largely dismissed them.

However, the studies align with—and bolster—the conspiracy theories and misinformation spread by the MAHA movement, which is led by ardent anti-vaccine activist and current US health secretary Robert F. Kennedy Jr. As health secretary, Kennedy has pledged to remove fluoride from municipal water, which, over decades, has proven safe and highly effective at preventing tooth decay in children. He has also, at various times, suggested 5G cell phone radiation causes cancer, a variety of other health conditions, changes to DNA, and is used as mass surveillance.

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The first people to set foot in Australia were fossil hunters

aboriginal australians, ancient people did stuff, Archaeology, australia, biological archaeology, Megafauna, megafaunal extinction, Science / Rejus Almole / October 23, 2025

I just think they’re neat

Europeans weren’t the first people to collect fossils in Australia.

Several species of short-faced kangaroos, like this one, once lived in Australia. Some stood two meters tall, while others were less than half a meter tall. Credit: By Ghedoghedo – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8398432

Australia’s First Peoples may or may not have hunted the continent’s megafauna to extinction, but they definitely collected fossils.

A team of archaeologists examined the fossilized leg bone of an extinct kangaroo and realized that instead of evidence of butchery, cut marks on the bone reveal an ancient attempt at fossil collecting. That leaves Australia with little evidence of First Peoples hunting or butchering the continent’s extinct megafauna—and reopens the question of whether humans were responsible for the die-off of that continent’s giant Ice Age marsupials.

Fossil hunting in the Ice Age

In the unsolved case of whether humans hunted Australia’s Ice Age megafauna to extinction, the key piece of evidence so far is a tibia (one of the bones of the lower leg) from an extinct short-faced kangaroo. Instead of hopping like their modern relatives, these extinct kangaroos walked on their hind legs, probably placing all their weight on the tips of single hoofed toes. This particular kangaroo wasn’t quite fully grown when it died, which happened sometime between 44,500 and 55,200 years ago, based on uranium-series dating of the thin layer of rock covering most of the fossils in Mammoth Cave (in what’s now Western Australia).

There’s a shallow, angled chunk cut out of the bone near one end. When archaeologists first noticed the cut in 1970 after carefully chipping away the crust of calcium carbonate that had formed over the bone, it looked like evidence that Pleistocene hunters had carved up the kangaroo to eat it. But in their recent paper, University of New South Wales archaeologist Michael Archer and his colleagues say that’s probably not what happened. Instead, they have a stranger idea: “We suggest here that the purpose of this effort may have been the retrieval of the fossils from the bone-rich late-Pleistocene deposit in Mammoth Cave after its discovery by First Peoples,” they wrote in their recent paper.

a photo of a fossil bone with a shallow chunk cut out of it — This close-up image shows the cut kangaroo bone and a micro-CT image of the surfaces of the cut. Credit: Archer et al. 2025

The world used to be so much weirder

Based on the available archaeological evidence, it looks like people first set foot on Australia sometime around 65,000 years ago. At the time, the continent was home to a bizarre array of giant marsupials, as well as flightless birds even bigger and scarier than today’s emus and cassowaries. For the next 20,000 years, Australia’s First Peoples shared the landscape with short-faced kangaroos; Zygomaturus trilobus, a hulking 500-kilogram marsupial that looked a little like a rhinoceros; and Diprotodon optatum, the largest marsupial that ever lived: a 3,000-kilogram behemoth that roamed in huge herds (picture a bear about the size of a bison with a woodchuck’s face).

These species died out sometime around 45,000 or 40,000 years ago; today, they live on in ancient rock art and stories, some of which seem to describe people interacting with now-extinct species.

Since they had shared the continent with humans for at least 20,000 years at that point, it doesn’t seem that the sudden arrival of humans caused an immediate mass extinction. But it’s possible that by hunting or even setting controlled fires, people may have put just enough strain on these megafauna species to make them vulnerable enough for the next climate upheaval to finish them off.

In some parts of the world, there’s direct evidence that Pleistocene people hunted or scavenged meat from the remains of now-extinct megafauna. Elsewhere, archaeologists are still debating whether humans, the inexorable end of the last Ice Age, or some combination of the two killed off the world’s great Ice Age giants. The interaction between people and their local ecosystems looked (and still looks) different everywhere, depending on culture, environment, and a host of other factors.

The jury is still out on what killed the megafauna in Australia because the evidence we need either hasn’t survived the intervening millennia or still lies buried somewhere, waiting to be found and studied. For decades, the one clear bit of evidence has seemed to be the Mammoth Cave short-faced kangaroo tibia. But Archer and his colleagues argue that even that isn’t a smoking gun.

An man in khakis and a dark blue shirt studies a cave wall. — An archaeologist examines a fossil deposit in the wall of Mammoth Cave, in Western Australia. 50,000 years ago, one of the earliest people on the continent may also have stood here contemplating the fossils. Credit: Archer et al. 2025

Evidence of rock collecting, not butchery

For one thing, the researchers argue that the kangaroo had been dead for a very long time when the cut was made. Nine long, thin cracks run along the length of the tibia, formed when the bone dried and shrank. And in the cut section, there’s a short crack running across the width of the bone—but it stops at either end when it meets the long cracks from the bone’s drying. That suggests the bone had already dried and shrunk, leaving those long cracks before the cut was made. It may have just been a very old bone, or it may have already begun to fossilize, but the meat would have been long gone, leaving behind a bone sticking out of the cave wall.

Since there’s no mark or dent on the opposite side of the bone from the cut (which would have happened if it were lying on the ground being butchered), it was probably sticking out of the fossil bed in the cave wall when someone came along and tried to cut it free. And since a crust of calcium carbonate had time to form over the cut (it covers most of the fossils in Mammoth Cave like a rocky burial shroud), that must have happened at least 44,000 years ago.

That leaves us with an interesting mental image: a member of one of Australia’s First Peoples, 45,000 years ago, exploring a cave filled with the bones of fantastical, long-dead animals. This ancient caver finds a bone sticking out from the cave wall and tries to hack the protruding end free—twice, from different angles—before giving up and leaving it in place.

People have always collected cool rocks

We can’t know for sure why this long-ago person wanted the bone in the first place. (Did it have a religious purpose? Might it have made a good tool? Was it just a cool souvenir?) We also don’t know why they gave up their attempt. But if Archer and his colleagues are right, the bone leaves Australia without any clear evidence that ancient people hunted—or even scavenged food from the remains of—extinct Pleistocene megafauna like short-faced kangaroos.

“This is not to say that it did not happen, just that there is now no hard evidence to support that it did,” Archer and his colleagues wrote in their recent paper. We don’t yet know exactly how Australia’s First Peoples interacted with these species.

But whether Archer and his colleagues are correct in their analysis of this particular kangaroo bone or not, humans around the world have been picking up fossils for at least tens of thousands of years. There’s evidence that people in Australia have collected and traded the fossils of extinct animals for pretty much as long as people have been in Australia, including everything from trilobites to Zygomaturus teeth and the jawbones of other extinct marsupials.

“What we can conclude,” Archer and his colleagues wrote, “is that the first people in Australia who demonstrated a keen interest in and collected fossils were First Peoples, probably thousands of years before Europeans set foot on that continent.”

Royal Society Open Science, 2025. DOI: 10.1098/rsos.250078 (About DOIs).

Kiona is a freelance science journalist and resident archaeology nerd at Ars Technica.

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Google has a useful quantum algorithm that outperforms a supercomputer

Computer science, Features, Google, NMR, Physics, quantum computing, quantum mechanics, Science / Paul Patrick / October 22, 2025

An approach it calls “quantum echoes” takes 13,000 times longer on a supercomputer.

The work relied on Google’s current-generation quantum hardware, the Willow chip. Credit: Google

A few years back, Google made waves when it claimed that some of its hardware had achieved quantum supremacy, performing operations that would be effectively impossible to simulate on a classical computer. That claim didn’t hold up especially well, as mathematicians later developed methods to help classical computers catch up, leading the company to repeat the work on an improved processor.

While this back-and-forth was unfolding, the field became less focused on quantum supremacy and more on two additional measures of success. The first is quantum utility, in which a quantum computer performs computations that are useful in some practical way. The second is quantum advantage, in which a quantum system completes calculations in a fraction of the time it would take a typical computer. (IBM and a startup called Pasqual have published a useful discussion about what would be required to verifiably demonstrate a quantum advantage.)

Today, Google and a large collection of academic collaborators are publishing a paper describing a computational approach that demonstrates a quantum advantage compared to current algorithms—and may actually help us achieve something useful.

Out of time

Google’s latest effort centers on something it’s calling “quantum echoes.” The approach could be described as a series of operations on the hardware qubits that make up its machine. These qubits hold a single bit of quantum information in a superposition between two values, with probabilities of finding the qubit in one value or the other when it’s measured. Each qubit is entangled with its neighbors, allowing its probability to influence those of all the qubits around it. The operations that allow computation, called gates, are ways of manipulating these probabilities. Most current hardware, including Google’s, perform manipulations on one or two qubits at a time (termed one- and two-qubit gates, respectively.

For quantum echoes, the operations involved performing a set of two-qubit gates, altering the state of the system, and later performing the reverse set of gates. On its own, this would return the system to its original state. But for quantum echoes, Google inserts single-qubit gates performed with a randomized parameter. This alters the state of the system before the reverse operations take place, ensuring that the system won’t return to exactly where it started. That explains the “echoes” portion of the name: You’re sending an imperfect copy back toward where things began, much like an echo involves the imperfect reversal of sound waves.

That’s what the process looks like in terms of operations performed on the quantum hardware. But it’s probably more informative to think of it in terms of a quantum system’s behavior. As Google’s Tim O’Brien explained, “You evolve the system forward in time, then you apply a small butterfly perturbation, and then you evolve the system backward in time.” The forward evolution is the first set of two qubit gates, the small perturbation is the randomized one qubit gate, and the second set of two qubit gates is the equivalent of sending the system backward in time.

Because this is a quantum system, however, strange things happen. “On a quantum computer, these forward and backward evolutions, they interfere with each other,” O’Brien said. One way to think about that interference is in terms of probabilities. The system has multiple paths between its start point and the point of reflection—where it goes from evolving forward in time to evolving backward—and from that reflection point back to a final state. Each of those paths has a probability associated with it. And since we’re talking about quantum mechanics, those paths can interfere with each other, increasing some probabilities at the expense of others. That interference ultimately determines where the system ends up.

(Technically, these are termed “out of time order correlations,” or OTOCs. If you read the Nature paper describing this work, prepare to see that term a lot.)

Demonstrating advantage

So how do you turn quantum echoes into an algorithm? On its own, a single “echo” can’t tell you much about the system—the probabilities ensure that any two runs might show different behaviors. But if you repeat the operations multiple times, you can begin to understand the details of this quantum interference. And performing the operations on a quantum computer ensures that it’s easy to simply rerun the operations with different random one-qubit gates and get many instances of the initial and final states—and thus a sense of the probability distributions involved.

This is also where Google’s quantum advantage comes from. Everyone involved agrees that the precise behavior of a quantum echo of moderate complexity can be modeled using any leading supercomputer. But doing so is very time-consuming, so repeating those simulations a few times becomes unrealistic. The paper estimates that a measurement that took its quantum computer 2.1 hours to perform would take the Frontier supercomputer approximately 3.2 years. Unless someone devises a far better classical algorithm than what we have today, this represents a pretty solid quantum advantage.

But is it a useful algorithm? The repeated sampling can act a bit like the Monte Carlo sampling done to explore the behavior of a wide variety of physical systems. Typically, however, we don’t view algorithms as modeling the behavior of the underlying hardware they’re being run on; instead, they’re meant to model some other physical system we’re interested in. That’s where Google’s announcement stands apart from its earlier work—the company believes it has identified an interesting real-world physical system with behaviors that the quantum echoes can help us understand.

That system is a small molecule in a Nuclear Magnetic Resonance (NMR) machine. In a second draft paper being published on the arXiv later today, Google has collaborated with a large collection of NMR experts to explore that use.

From computers to molecules

NMR is based on the fact that the nucleus of every atom has a quantum property called spin. When nuclei are held near to each other, such as when they’re in the same molecule, these spins can influence one another. NMR uses magnetic fields and photons to manipulate these spins and can be used to infer structural details, like how far apart two given atoms are. But as molecules get larger, these spin networks can extend for greater distances and become increasingly complicated to model. So NMR has been limited to focusing on the interactions of relatively nearby spins.

For this work, though, the researchers figured out how to use an NMR machine to create the physical equivalent of a quantum echo in a molecule. The work involved synthesizing the molecule with a specific isotope of carbon (carbon-13) in a known location in the molecule. That isotope could be used as the source of a signal that propagates through the network of spins formed by the molecule’s atoms.

“The OTOC experiment is based on a many-body echo, in which polarization initially localized on a target spin migrates through the spin network, before a Hamiltonian-engineered time-reversal refocuses to the initial state,” the team wrote. “This refocusing is sensitive to perturbations on distant butterfly spins, which allows one to measure the extent of polarization propagation through the spin network.”

Naturally, something this complicated needed a catchy nickname. The team came up with TARDIS, or Time-Accurate Reversal of Dipolar InteractionS. While that name captures the “out of time order” aspect of OTOC, it’s simply a set of control pulses sent to the NMR sample that starts a perturbation of the molecule’s network of nuclear spins. A second set of pulses then reflects an echo back to the source.

The reflections that return are imperfect, with noise coming from two sources. The first is simply imperfections in the control sequence, a limitation of the NMR hardware. But the second is the influence of fluctuations happening in distant atoms along the spin network. These happen at a certain frequency at random, or the researchers could insert a fluctuation by targeting a specific part of the molecule with randomized control signals.

The influence of what’s going on in these distant spins could allow us to use quantum echoes to tease out structural information at greater distances than we currently do with NMR. But to do so, we need an accurate model of how the echoes will propagate through the molecule. And again, that’s difficult to do with classical computations. But it’s very much within the capabilities of quantum computing, which the paper demonstrates.

Where things stand

For now, the team stuck to demonstrations on very simple molecules, making this work mostly a proof of concept. But the researchers are optimistic that there are many ways the system could be used to extract structural information from molecules at distances that are currently unobtainable using NMR. They list a lot of potential upsides that should be explored in the discussion of the paper, and there are plenty of smart people who would love to find new ways of using their NMR machines, so the field is likely to figure out pretty quickly which of these approaches turns out to be practically useful.

The fact that the demonstrations were done with small molecules, however, means that the modeling run on the quantum computer could also have been done on classical hardware (it only required 15 hardware qubits). So Google is claiming both quantum advantage and quantum utility, but not at the same time. The sorts of complex, long-distance interactions that would be out of range of classical simulation are still a bit beyond the reach of the current quantum hardware. O’Brien estimated that the hardware’s fidelity would have to improve by a factor of three or four to model molecules that are beyond classical simulation.

The quantum advantage issue should also be seen as a work in progress. Google has collaborated with enough researchers at enough institutions that there’s unlikely to be a major improvement in algorithms that could allow classical computers to catch up. Until the community as a whole has some time to digest the announcement, though, we shouldn’t take that as a given.

The other issue is verifiability. Some quantum algorithms will produce results that can be easily verified on classical hardware—situations where it’s hard to calculate the right result but easy to confirm a correct answer. Quantum echoes isn’t one of those, so we’ll need another quantum computer to verify the behavior Google has described.

But Google told Ars nothing is up to the task yet. “No other quantum processor currently matches both the error rates and number of qubits of our system, so our quantum computer is the only one capable of doing this at present,” the company said. (For context, Google says that the algorithm was run on up to 65 qubits, but the chip has 105 qubits total.)

There’s a good chance that other companies would disagree with that contention, but it hasn’t been possible to ask them ahead of the paper’s release.

In any case, even if this claim proves controversial, Google’s Michel Devoret, a recent Nobel winner, hinted that we shouldn’t have long to wait for additional ones. “We have other algorithms in the pipeline, so we will hopefully see other interesting quantum algorithms,” Devoret said.

Nature, 2025. DOI: 10.1038/s41586-025-09526-6 (About DOIs).

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“Butt breathing” might soon be a real medical treatment

human physiology, Ig Nobel Prizes, medicine, physiology, Science / Paul Patrick / October 21, 2025

And Oxycyte was ideal for the group’s 2021 Ig Nobel-winning efforts. The experiments involved intra-anally administering oxygen gas or a liquid oxygenated perfluorocarbon to the unfortunate rodents and porcines. Yes, they gave the animals enemas. They then induced respiratory failure and evaluated the effectiveness of the intra-anal treatment. The result: Both treatments were pretty darned effective at staving off respiratory failure with no major complications.

Visual abstract shows highlights of first human clinical trial to evaluate the safety of enteral ventilation concept — Credit: Cincinnati Children’s/Med

So far, so good. The next logical step was to determine if EVA could work in human patients, too. “Patients with severe respiratory failure often need mechanical ventilation to survive, but these therapies can cause further lung injury,” the authors wrote in this latest paper. EVA “could give the lungs a chance to rest and heal.”

The team recruited 27 healthy adult men in Japan, each of whom received a dose of non-oxygenated perfluorodecalin via the anus. They were asked to retain the liquid for a full hour as the dosage slowly increased from 25 to 1,500 mL. Twenty of the men successfully completed the experiment. Apart from mild temporary abdominal bloating and discomfort—which proved to be dosage dependent and resolved with no need for medical attention—they experienced no adverse effects.

“This is the first human data and the results are limited solely to demonstrating the safety of the procedure and not its effectiveness,” said co-author Takanori Takebe of Cincinnati Children’s Hospital and the University of Osaka in Japan. “But now that we have established tolerance, the next step will be to evaluate how effective the process is for delivering oxygen to the bloodstream.”

Med, 2025. DOI: 10.1016/j.medj.2025.100887 (About DOIs).

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Breaking down rare earth element magnets for recycling

chemistry, rare earth elements, recycling, Science / Mike M. / October 20, 2025

All the world’s discarded phones, bricked laptops, and other trashed electronics are collectively a treasure trove of rare earth elements (REEs). But separating out and recovering these increasingly sought-after materials is no easy task.

However, a team of researchers says it has developed a way of separating REEs from waste—magnets, in this case—that is relatively easy, uses less energy, and isn’t nearly as emissions and pollution intensive as current methods. The team published a paper describing this method in the Proceedings of the National Academy of Sciences.

In short, this process involves using an electric current to heat waste magnets to very high temperatures very fast, and using chlorine gas to react with the non-REEs in the mix, keeping them in the vapor phase. James Tour, one of the authors and a professor of materials science and nanoengineering at Rice University, says that the research can help the United States meet its growing need for these elements.

“The country’s scurrying to try to see how we can get these [REEs],” he says. “And, in our argument, it’s all in our waste… We have it right here, just pull it right back out of the waste.”

Getting hot in here

In 2018, Tour and his colleagues discovered that this rapid heating process, called flash joule heating, can turn any carbon source—including coal, biochar, and mixed plastic—into graphene, a very thin, strong, and conductive material.

Building on this, in 2023, they developed a method that uses flash joule heating and chlorine. In this work, they identified the Gibbs free energy, the reactivity of a material, for the oxide form of all 17 REEs and nine common oxides found in REE waste.

Ground-up waste magnets are put on a platform made of carbon and surrounded by a glass chamber. A current runs through the platform, rapidly producing immense heat, thousands of degrees celsius in a matter of seconds. Chlorine gas is then released into the chamber, creating chlorides of unwanted elements like iron and lowering their boiling points.

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Do animals fall for optical illusions? It’s complicated.

animal cognition, animal perception, animal psychology, Ebbinghaus illusion, psychology, Science / Kris Guyer / October 20, 2025

A tale of two species

View from above of the apparatuses used for ring doves (A) and guppies (B). Credit: M. Santaca et al., 2025

The authors tested 38 ring doves and 19 guppies (of the “snakeskin cobra green” ornamental strain) for their experiments. The doves were placed in a testing cage with the bottom covered with an anti-slip wooden panel and a branch serving as a perch and starting point; the feeding station was at the opposite end of the cage. The guppies were tested in single tanks with a gravel bottom.

In both cases, the test subjects were presented with visual stimuli in the form of two white plastic cards. Sizes differed for the doves and the guppies, but each card showed an array of six black circles with a bit of food serving as the center “circle”: red millet seeds for the doves and commercial flake food for the guppies. The circles were smaller on one of the cards and larger on the other. The subjects were free to choose food from one of the cards, and the card with the unchosen food was removed promptly. If no choice was made after 15 minutes, the trial was null and the team tried again after a 15-minute interval.

The authors found that the guppies were indeed highly susceptible to the Ebbinghaus illusion, choosing food surrounded by smaller circles much more frequently, suggesting they perceived it as larger and hence more desirable. The results for ring doves were more mixed, however: some of the doves seemed to be susceptible while others were not, suggesting that their perceptual strategies are more local, detail-oriented, and less influenced by their surrounding context.

“The doves’ mixed responses suggest that individual experience or innate bias can strongly shape how an animal interprets illusions,” the authors concluded. “Just like in humans, where some people are strongly fooled by illusions and others hardly at all, animal perception is not uniform.”

The authors acknowledge that their study has limitations. For instance, guppies and ring doves diverged hundreds of millions of years ago and hence are phylogenetically distant, so the perceptual differences between them could be due not just to ecological pressures, but also to evolutionary traits gained or lost via natural selection. Future experiments involving more closely related species with different sensory environments would better isolate the role of ecological factors in animal perception.

Frontiers in Psychology, 2025. DOI: 10.3389/fpsyg.2025.1653695 (About DOIs).

Do animals fall for optical illusions? It’s complicated. Read More »

Dead Ends is a fun, macabre medical history for kids

books, children's books, culture, medical history, medicine, Science / Tim Belzer / October 17, 2025

flukes, flops, and failures

Ars chats with co-authors Lindsey Fitzharris and Adrian Teal about their delightful new children’s book.

In 1890, a German scientist named Robert Koch thought he’d invented a cure for tuberculosis, a substance derived from the infecting bacterium itself that he dubbed Tuberculin. His substance didn’t actually cure anyone, but it was eventually widely used as a diagnostic skin test. Koch’s successful failure is just one of the many colorful cases featured in Dead Ends! Flukes, Flops, and Failures that Sparked Medical Marvels, a new nonfiction illustrated children’s book by science historian Lindsey Fitzharris and her husband, cartoonist Adrian Teal.

A noted science communicator with a fondness for the medically macabre, Fitzharris published a biography of surgical pioneer Joseph Lister, The Butchering Art, in 2017—a great, if occasionally grisly, read. She followed up with 2022’s The Facemaker: A Visionary Surgeon’s Battle to Mend the Disfigured Soldiers of World War I, about a WWI surgeon named Harold Gillies who rebuilt the faces of injured soldiers.

And in 2020, she hosted a documentary for the Smithsonian Channel, The Curious Life and Death Of…, exploring famous deaths, ranging from drug lord Pablo Escobar to magician Harry Houdini. Fitzharris performed virtual autopsies, experimented with blood samples, interviewed witnesses, and conducted real-time demonstrations in hopes of gleaning fresh insights. For his part, Teal is a well-known caricaturist and illustrator, best known for his work on the British TV series Spitting Image. His work has also appeared in The Guardian and the Sunday Telegraph, among other outlets.

The couple decided to collaborate on children’s books as a way to combine their respective skills. Granted, “[The market for] children’s nonfiction is very difficult,” Fitzharris told Ars. “It doesn’t sell that well in general. It’s very difficult to get publishers on board with it. It’s such a shame because I really feel that there’s a hunger for it, especially when I see the kids picking up these books and loving it. There’s also just a need for it with the decline in literacy rates. We need to get people more engaged with these topics in ways that go beyond a 30-second clip on TikTok.”

Their first foray into the market was 2023’s Plague-Busters! Medicine’s Battles with History’s Deadliest Diseases, exploring “the ickiest illnesses that have infected humans and affected civilizations through the ages”—as well as the medical breakthroughs that came about to combat those diseases. Dead Ends is something of a sequel, focusing this time on historical diagnoses, experiments, and treatments that were useless at best, frequently harmful, yet eventually led to unexpected medical breakthroughs.

Failure is an option

The book opens with the story of Robert Liston, a 19th-century Scottish surgeon known as “the fastest knife in the West End,” because he could amputate a leg in less than three minutes. That kind of speed was desirable in a period before the discovery of anesthetic, but sometimes Liston’s rapid-fire approach to surgery backfired. One story (possibly apocryphal) holds that Liston accidentally cut off the finger of his assistant in the operating theater as he was switching blades, then accidentally cut the coat of a spectator, who died of fright. The patient and assistant also died, so that operation is now often jokingly described as the only one with a 300 percent mortality rate, per Fitzharris.

Liston is the ideal poster child for the book’s theme of celebrating the role of failure in scientific progress. “I’ve always felt that failure is something we don’t talk about enough in the history of science and medicine,” said Fitzharris. “For everything that’s succeeded there’s hundreds, if not thousands, of things that’s failed. I think it’s a great concept for children. If you think that you’ve made mistakes, look at these great minds from the past. They’ve made some real whoppers. You are in good company. And failure is essential to succeeding, especially in science and medicine.”

“During the COVID pandemic, a lot of people were uncomfortable with the fact that some of the advice would change, but to me that was a comfort because that’s what you want to see scientists and doctors doing,” she continued. “They’re learning more about the virus, they’re changing their advice. They’re adapting. I think that this book is a good reminder of what the scientific process involves.”

The details of Liston’s most infamous case might be horrifying, but as Teal observes, “Comedy equals tragedy plus time.” One of the reasons so many of his patients died was because this was before the broad acceptance of germ theory and Joseph Lister’s pioneering work on antiseptic surgery. Swashbuckling surgeons like Liston prided themselves on operating in coats stiffened with blood—the sign of a busy and hence successful surgeon. Frederick Treves once observed that in the operating room, “cleanliness was out of place. It was considered to be finicking and affected. An executioner might as well manicure his nails before chopping off a head.”

“There’s always a lot of initial resistance to new ideas, even in science and medicine,” said Teal. “A lot of what we talk about is paradigm shifts and the difficulty of achieving [such a shift] when people are entrenched in their thinking. Galen was a hugely influential Roman doctor and got a lot of stuff right, but also got a lot of stuff wrong. People were clinging onto that stuff for centuries. You have misunderstanding compounded by misunderstanding, century after century, until somebody finally comes along and says, ‘Hang on a minute, this is all wrong.’”

You know… for kids

Writing for children proved to be a very different experience for Fitzharris after two adult-skewed science history books. “I initially thought children’s writing would be easy,” she confessed. “But it’s challenging to take these high-level concepts and complex stories about past medical movements and distill them for children in an entertaining and fun way.” She credits Teal—a self-described “man-child”—for taking her drafts and making them more child-friendly.

Teal’s clever, slightly macabre illustrations also helped keep the book accessible to its target audience, appealing to children’s more ghoulish side. “There’s a lot of gruesome stuff in this book,” Teal said. “Obviously it’s for kids, so you don’t want to go over the top, but equally, you don’t want to shy away from those details. I always say kids love it because kids are horrible, in the best possible way. I think adults sometimes worry too much about kids’ sensibilities. You can be a lot more gruesome than you think you can.”

The pair did omit some darker subject matter, such as the history of frontal lobotomies, notably the work of a neuroscientist named Walter Freeman, who operated an actual “lobotomobile.” For the authors, it was all about striking the right balance. “How much do you give to the kids to keep them engaged and interested, but not for it to be scary?” said Fitzharris. “We don’t want to turn people off from science and medicine. We want to celebrate the greatness of what we’ve achieved scientifically and medically. But we also don’t want to cover up the bad bits because that is part of the process, and it needs to be acknowledged.”

Sometimes Teal felt it just wasn’t necessary to illustrate certain gruesome details in the text—such as their discussion of the infamous case of Phineas Gage. Gage was a railroad construction foreman. In 1848, he was overseeing a rock blasting team when an explosion drove a three-foot tamping iron through his skull. “There’s a horrible moment when [Gage] leans forward and part of his brain drops out,” said Teal. “I’m not going to draw that, and I don’t need to, because it’s explicit in the text. If we’ve done a good enough job of writing something, that will put a mental picture in someone’s head.”

Miraculously, Gage survived, although there were extreme changes in his behavior and personality, and his injuries eventually caused epileptic seizures, one of which killed Gage in 1860. Gage became the index case for personality changes due to frontal lobe damage, and 50 years after his death, the case inspired neurologist David Ferrier to create brain maps based on his research into whether certain areas of the brain controlled specific cognitive functions.

“Sometimes it takes a beat before we get there,” said Fitzharris. “Science builds upon ideas, and it can take time. In the age of looking for instantaneous solutions, I think it’s important to remember that research needs to allow itself to do what it needs to do. It shouldn’t just be guided by an end goal. Some of the best discoveries that were made had no end goal in mind. And if you read Dead Ends, you’re going to be very happy that you live in 2025. Medically speaking, this is the best time. That’s really what Dead Ends is about. It’s a celebration of how far we’ve come.”

Jennifer is a senior writer at Ars Technica with a particular focus on where science meets culture, covering everything from physics and related interdisciplinary topics to her favorite films and TV series. Jennifer lives in Baltimore with her spouse, physicist Sean M. Carroll, and their two cats, Ariel and Caliban.

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NASA’s next Moonship reaches last stop before launch pad

artemis, artemis II, human spaceflight, Kennedy Space Center, launch, Lockheed Martin, moon, NASA, orion, Science, Space, space launch system, vehicle assembly building / Kris Guyer / October 17, 2025

The Orion spacecraft, which will fly four people around the Moon, arrived inside the cavernous Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida late Thursday night, ready to be stacked on top of its rocket for launch early next year.

The late-night transfer covered about 6 miles (10 kilometers) from one facility to another at the Florida spaceport. NASA and its contractors are continuing preparations for the Artemis II mission after the White House approved the program as an exception to work through the ongoing government shutdown, which began on October 1.

The sustained work could set up Artemis II for a launch opportunity as soon as February 5 of next year. Astronauts Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen will be the first humans to fly on the Orion spacecraft, a vehicle that has been in development for nearly two decades. The Artemis II crew will make history on their 10-day flight by becoming the first people to travel to the vicinity of the Moon since 1972.

Where things stand

The Orion spacecraft, developed by Lockheed Martin, has made several stops at Kennedy over the last few months since leaving its factory in May.

First, the capsule moved to a fueling facility, where technicians filled it with hydrazine and nitrogen tetroxide propellants, which will feed Orion’s main engine and maneuvering thrusters on the flight to the Moon and back. In the same facility, teams loaded high-pressure helium and ammonia coolant into Orion propulsion and thermal control systems.

The next stop was a nearby building where the Launch Abort System was installed on the Orion spacecraft. The tower-like abort system would pull the capsule away from its rocket in the event of a launch failure. Orion stands roughly 67 feet (20 meters) tall with its service module, crew module, and abort tower integrated together.

Teams at Kennedy also installed four ogive panels to serve as an aerodynamic shield over the Orion crew capsule during the first few minutes of launch.

The Orion spacecraft, with its Launch Abort System and ogive panels installed, is seen last month inside the Launch Abort System Facility at Kennedy Space Center, Florida. Credit: NASA/Frank Michaux

It was then time to move Orion to the Vehicle Assembly Building (VAB), where a separate team has worked all year to stack the elements of NASA’s Space Launch System rocket. In the coming days, cranes will lift the spacecraft, weighing 78,000 pounds (35 metric tons), dozens of stories above the VAB’s center aisle, then up and over the transom into the building’s northeast high bay to be lowered atop the SLS heavy-lift rocket.

NASA’s next Moonship reaches last stop before launch pad Read More »

Lead poisoning has been a feature of our evolution

anthropology, Archaeology, australopithecus, hominins, lead poisoning, Neanderthals, paleoanthropology, Science / Kris Guyer / October 17, 2025

A recent study found lead in teeth from 2 million-year-old hominin fossils.

Our hominid ancestors faced a Pleistocene world full of dangers—and apparently one of those dangers was lead poisoning.

Lead exposure sounds like a modern problem, at least if you define “modern” the way a paleoanthropologist might: a time that started a few thousand years ago with ancient Roman silver smelting and lead pipes. According to a recent study, however, lead is a much more ancient nemesis, one that predates not just the Romans but the existence of our genus Homo. Paleoanthropologist Renaud Joannes-Boyau of Australia’s Southern Cross University and his colleagues found evidence of exposure to dangerous amounts of lead in the teeth of fossil apes and hominins dating back almost 2 million years. And somewhat controversially, they suggest that the toxic element’s pervasiveness may have helped shape our evolutionary history.

The skull of an early hominid, aged to a dark brown color. The skull is fragmentary, but the fragments are held in the appropriate locations by an underlying beige material. — The skull of an early hominid. Credit: Einsamer Schütze / Wikimedia

The Romans didn’t invent lead poisoning

Joannes-Boyau and his colleagues took tiny samples of preserved enamel and dentin from the teeth of 51 fossils. In most of those teeth, the paleoanthropologists found evidence that these apes and hominins had been exposed to lead—sometimes in dangerous quantities—fairly often during their early years.

Tooth enamel forms in thin layers, a little like tree rings, during the first six or so years of a person’s life. The teeth in your mouth right now (and of which you are now uncomfortably aware; you’re welcome) are a chemical and physical record of your childhood health—including, perhaps, whether you liked to snack on lead paint chips. Bands of lead-tainted tooth enamel suggest that a person had a lot of lead in their bloodstream during the year that layer of enamel was forming (in this case, “a lot” means an amount measurable in parts per million).

In 71 percent of the hominin teeth that Joannes-Boyau and his colleagues sampled, dark bands of lead in the tooth enamel showed “clear signs of episodic lead exposure” during the crucial early childhood years. Those included teeth from 100,000-year-old members of our own species found in China and 250,000-year-old French Neanderthals. They also included much earlier hominins who lived between 1 and 2 million years ago in South Africa: early members of our genus Homo, along with our relatives Australopithecus africanus and Paranthropus robustus. Lead exposure, it turns out, is a very ancient problem.

Living in a dangerous world

This study isn’t the first evidence that ancient hominins dealt with lead in their environments. Two Neanderthals living 250,000 years ago in France experienced lead exposure as young children, according to a 2018 study. At the time, they were the oldest known examples of lead exposure (and they’re included in Joannes-Boyau and his colleagues’ recent study).

Until a few thousand years ago, no one was smelting silver, plumbing bathhouses, or releasing lead fumes in car exhaust. So how were our hominin ancestors exposed to the toxic element? Another study, published in 2015, showed that the Spanish caves occupied by other groups of Neanderthals contained enough heavy metals, including lead, to “meet the present-day standards of ‘contaminated soil.’”

Today, we mostly think of lead in terms of human-made pollution, so it’s easy to forget that it’s also found naturally in bedrock and soil. If that weren’t the case, archaeologists couldn’t use lead isotope ratios to tell where certain artifacts were made. And some places—and some types of rock—have higher lead concentrations than others. Several common minerals contain lead compounds, including galena or lead sulfide. And the kind of lead exposure documented in Joannes-Boyau and his colleagues’ study would have happened at an age when little hominins were very prone to putting rocks, cave dirt, and other random objects in their mouths.

Some of the fossils from the Queque cave system in China, which included a 1.8 million-year-old extinct gorilla-like ape called Gigantopithecus blacki, had lead levels higher than 50 parts per million, which Joannes-Boyau and his colleagues describe as “a substantial level of lead that could have triggered some developmental, health, and perhaps social impairments.”

Even for ancient hominins who weren’t living in caves full of lead-rich minerals, wildfires, or volcanic eruptions can also release lead particles into the air, and erosion or flooding can sweep buried lead-rich rock or sediment into water sources. If you’re an Australopithecine living upstream of a lead-rich mica outcropping, for example, erosion might sprinkle poison into your drinking water—or the drinking water of the gazelle you eat or the root system of the bush you get those tasty berries from… .

Our world is full of poisons. Modern humans may have made a habit of digging them up and pumping them into the air, but they’ve always been lying in wait for the unwary.

screenshot from the app — Cubic crystals of the lead-sulfide mineral galena.

Digging into the details

Joannes-Boyau and his colleagues sampled the teeth of several hominin species from South Africa, all unearthed from cave systems just a few kilometers apart. All of them walked the area known as Cradle of Humankind within a few hundred thousand years of each other (at most), and they would have shared a very similar environment. But they also would have had very different diets and ways of life, and that’s reflected in their wildly different exposures to lead.

A. africanus had the highest exposure levels, while P. robustus had signs of infrequent, very slight exposures (with Homo somewhere in between the two). Joannes-Boyau and his colleagues chalk the difference up to the species’ different diets and ecological niches.

“The different patterns of lead exposure could suggest that P. robustus lead bands were the result of acute exposure (e.g., wild forest fire),” Joannes-Boyau and his colleagues wrote, “while for the other two species, known to have a more varied diet, lead bands may be due to more frequent, seasonal, and higher lead concentration through bioaccumulation processes in the food chain.”

Did lead exposure affect our evolution?

Given their evidence that humans and their ancestors have regularly been exposed to lead, the team looked into whether this might have influenced human evolution. In doing so, they focused on a gene called NOVA1, which has been linked to both brain development and the response to lead exposure. The results were quite a bit short of decisive; you can think of things as remaining within the realm of a provocative hypothesis.

The NOVA1 gene encodes a protein that influences the processing of messenger RNAs, allowing it to control the production of closely related variants of a single gene. It’s notable for a number of reasons. One is its role in brain development; mice without a working copy of NOVA1 die shortly after birth due to defects in muscle control. Its activity is also altered following exposure to lead.

But perhaps its most interesting feature is that modern humans have a version of the gene that differs by a single amino acid from the version found in all other primates, including our closest relatives, the Denisovans and Neanderthals. This raises the prospect that the difference is significant from an evolutionary perspective. Altering the mouse version so that it is identical to the one found in modern humans does alter the vocal behavior of these mice.

But work with human stem cells has produced mixed results. One group, led by one of the researchers involved in this work, suggested that stem cells carrying the ancestral form of the protein behaved differently from those carrying the modern human version. But others have been unable to replicate those results.

Regardless of that bit of confusion, the researchers used the same system, culturing stem cells with the modern human and ancestral versions of the protein. These clusters of cells (called organoids) were grown in media containing two different concentrations of lead, and changes in gene activity and protein production were examined. The researchers found changes, but the significance isn’t entirely clear. There were differences between the cells with the two versions of the gene, even without any lead present. Adding lead could produce additional changes, but some of those were partially reversed if more lead was added. And none of those changes were clearly related either to a response to lead or the developmental defects it can produce.

The relevance of these changes isn’t obvious, either, as stem cell cultures tend to reflect early neural development while the lead exposure found in the fossilized remains is due to exposure during the first few years of life.

So there isn’t any clear evidence that the variant found in modern humans protects individuals who are exposed to lead, much less that it was selected by evolution for that function. And given the widespread exposure seen in this work, it seems like all of our relatives—including some we know modern humans interbred with—would also have benefited from this variant if it was protective.

Science Advances, 2025. DOI: 10.1126/sciadv.adr1524 (About DOIs).

Kiona is a freelance science journalist and resident archaeology nerd at Ars Technica.

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