Biology

Tiny, 45 base long RNA can make copies of itself

biochemistry, Biology, evolution, origin of life, ribozymes, RNA, Science / Shannon Garcia / February 13, 2026

Self-copying RNAs may have been a key stop along the pathway to life.

By base pairing with themselves, RNAs can form complex structures with enzymatic activity. Credit: Laguna Design

There are plenty of unanswered questions about the origin of life on Earth. But the research community has largely reached consensus that one of the key steps was the emergence of an RNA molecule that could replicate itself. RNA, like its more famous relative DNA, can carry genetic information. But it can also fold up into three-dimensional structures that act as catalysts. These two features have led to the suggestion that early life was protein-free, with RNA handling both heredity and catalyzing a simple metabolism.

For this to work, one of the reactions that the early RNAs would need to catalyze is the copying of RNA molecules, without which any sort of heritability would be impossible. While we’ve found a number of catalytic RNAs that can copy other molecules, none have been able to perform a key reaction: making a copy of themselves. Now, however, a team has found an incredibly short piece of RNA—just 45 bases long—that can make a copy of itself.

Finding an RNA polymerase

We have identified a large number of catalytic RNAs (generically called ribozymes, for RNA-based enzymes), and some of them can catalyze reactions involving other RNAs. A handful of these are ligases, which link together two RNA molecules. In some cases, they need these molecules to be held together by a third RNA molecule that base pairs with both of them. We’ve only identified a few that can act as polymerases, which add RNA bases to a growing molecule, one at a time, with each new addition base pairing with a template molecule.

Black on white image showing 3 different enzymatic activities. One links any two nucleic acid strands, the other only links base paired strands, and the third links one base at a time. — Some ligases can link two nucleic acid strands (left), while others can link the strands only if they’re held together by base pairing with a template (center). A polymerase can be thought of as a template-dependent ligase that adds one base at a time. The newly discovered ribozyme sits somewhere between a template-directed ligase and a polymerase. Credit: John Timmer

Obviously, there is some functional overlap between them, as you can think of a polymerase as ligating on one base at a time. And in fact, at the ribozyme level, there’s some real-world overlap, as some ribozymes that were first identified as ligases were converted into polymerases by selecting for this new function.

While this is fascinating, there are a few problems with these known examples of polymerase ribozymes. One is that they’re long. So long, in fact, that they’re beyond the length of the sort of molecules that we’ve observed forming spontaneously from a mix of individual RNA bases. This length also means they’re largely incapable of making copies of themselves—the reactions are slow and inefficient enough that they simply stop before copying the entire molecule.

Another factor related to their length is that they tend to form very complex structures, with many different areas of the molecule base-paired to one another. That leaves very little of the molecule in a single-stranded form, which is needed to make a copy.

Based on past successes, a French-UK team decided to start a search for a polymerase by looking for a ligase. And they limited that search in an important way: They only tested short molecules. They started with pools of RNA molecules, each with a different random sequence, ranging from 40 to 80 bases. Overall, they estimated that they made a population of 10¹³ molecules out of the total possible population of 10²⁴ sequences of this type.

These random molecules were fed a collection of three-base-long RNAs, each linked to a chemical tag. The idea was that if a molecule is capable of ligating one of these short RNA fragments to itself, it could be pulled out using the tag. The mixtures were then placed in a salty mixture of water and ice, as this can promote reactions involving RNAs.

After 11 rounds of reactions and tag-based purification, the researchers ended up with three different RNA molecules that could each ligate three-base-long RNAs to existing molecules. Each of these molecules was subjected to mutagenesis and further rounds of selection. This ultimately left the researchers with a single, 51-base-long molecule that could add clusters of three bases to a growing RNA strand, depending on their ability to base-pair with an RNA template. They called this “polymerase QT-51,” with QT standing for “quite tiny.” They later found that they could shorten this to QT-45 without losing significant enzyme activity.

Checking its function

The basic characterization of QT-45 showed that it has some very impressive properties for a molecule that, by nucleic acid standards, is indeed quite tiny. While it was selected for linking collections of molecules that were three bases long, it could also link longer RNAs, work on shorter two-base molecules, or even add a single base at a time, though this was less efficient. While it worked slowly, the molecule’s active half-life was well over 100 days, so it had plenty of time to get things done before it degraded.

It also didn’t need to interact with any specific RNA sequences to work, suggesting it had a general affinity for RNA molecules. As a result, it wasn’t especially picky about the sequences it could copy.

As you might expect from such a small molecule, QT-45 didn’t tolerate changes to its own sequence very well—nearly the entire molecule was important in one way or another. Tests that involved changing every single individual base one at a time showed that almost all the changes reduced the ribozyme’s activity. There were, however, a handful of changes that improved things, suggesting that further selection could potentially yield additional improvements. And the impact of mutations near the center of the sequence was far more severe, suggesting that region is critical for QT-45’s enzymatic activity.

The team then started testing its ability to synthesize copies of other RNA molecules when given a mixture of all possible three-base sequences. One of the tests included a large stretch in which one end of the sequence base-paired with the other. To copy that, those base pairs need to somehow be pried apart. But QT-45 was able to make a copy, meaning it synthesized a strand that was able to base pair with the original.

It was also able to make a copy of a template strand that would base pair with a small ribozyme. That copying produced an active ribozyme.

But the key finding was that it could synthesize a sequence that base-pairs with itself, and then synthesize itself by copying that sequence. This was horribly inefficient and took months, but it happened.

Throughout these experiments, the fidelity averaged about 95 percent, meaning that, in copying itself, it would make an average of two to three errors. While this means a fair number of its copies wouldn’t be functional, it also means the raw materials for an evolutionary selection for improved function—random mutations—would be present.

What this means

It’s worth taking a moment to consider the use of three-base RNA fragments by this enzyme. On the surface, this may seem a bit like cheating, since current RNA polymerases add sequence one base at a time. But in reality, any chemical environment that could spontaneously assemble an RNA molecule 45 bases long will produce many fragments shorter than that. So in many ways, this might be a more realistic model of the conditions in which life emerged.

The authors note that these shorter fragments may be essential for QT-45’s activity. The short ribozyme probably doesn’t have the ability to enzymatically pry base-paired strands of RNA apart to copy them. But in a mixture of lots of small fragments, there’s likely to be an equilibrium, with some base-paired sequences spontaneously popping open and temporarily base pairing with a shorter fragment. Working with these base-paired fragments is probably essential to the ribozyme’s overall activity.

Right now, QT-45 isn’t an impressive enzyme. But the researchers point out that it has only been through 18 rounds of selection, which isn’t much. The most efficient ribozyme polymerases we have at present have been worked on by multiple labs for years. I expect QT-45 to receive similar attention and improve significantly over time.

Also notable is that the team came up with three different ligases in a test of just a small subset of the possible total RNA population of this size. If that frequency holds, there are on the order of 10¹¹ ligating ribozymes among the sequences of this size. Which raises the possibility that we could find far more if we do an exhaustive search. That suggests the first self-copying RNA might not be as improbable as it seems at first.

Science, 2026. DOI: 10.1126/science.adt2760 (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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Bringing the “functionally extinct” American chestnut back from the dead

American chestnut, Biology, extinction, genetic engineering, Genetics, Genomics, Invasive species, pathogens, plants, Science, trees / Beth Washington / February 12, 2026

Wiped out in its native range by invasive pathogens, the trees may make a comeback.

Very few people alive today have seen the Appalachian forests as they existed a century ago. Even as state and national parks preserved ever more of the ecosystem, fungal pathogens from Asia nearly wiped out one of the dominant species of these forests, the American chestnut, killing an estimated 3 billion trees. While new saplings continue to sprout from the stumps of the former trees, the fungus persists, killing them before they can seed a new generation.

But thanks in part to trees planted in areas where the two fungi don’t grow well, the American chestnut isn’t extinct. And efforts to revive it in its native range have continued, despite the long generation times needed to breed resistant trees. In Thursday’s issue of Science, researchers describe their efforts to apply modern genomic techniques and exhaustive testing to identify the best route to restoring chestnuts to their native range.

Multiple paths to restoration

While the American chestnut is functionally extinct—it’s no longer a participant in the ecosystems it once dominated—it’s most certainly not extinct. Two Asian fungi that have killed it off in its native range; one causes chestnut blight, while a less common pathogen causes a root rot disease. Both prefer warmer, humid environments and persist there because they can grow asymptomatically on distantly related trees, such as oaks. Still, chestnuts planted outside the species’ original range—primarily in drier areas of western North America—have continued to thrive.

There is also a virus that attacks the chestnut blight fungus, allowing a few trees to survive in areas where that virus is common. Finally, a handful of trees have grown to maturity in the American chestnut’s original range. These trees, which the paper refers to as LSACs (large surviving American chestnuts), suggest that there might have been some low level of natural resistance within the now-vanished population.

Those trees are central to one of the efforts to restore the American chestnut. If enough of them have distinct means of resisting the fungi, interbreeding them might produce a strain that not only survives the fungi but can also thrive in the Appalachians.

A related approach took advantage of the fact that the American chestnut can produce fertile hybrids with the Chinese chestnut, which had co-evolved with the introduced fungi and were thus resistant to lethal infections. The hope was that continued back-breeding of these hybrids with American chestnuts would result in trees that were very similar to American chestnuts yet retained the fungal resistance of their Asian cousins.

Both efforts suffered from the same problem that faces any biologist working on trees: They are slow-growing and can take years to reach a size at which they produce seeds. The situation was further complicated by the fact that the American chestnut can’t pollinate itself, so you need at least two trees before any breeding is possible.

Concerned about what this might mean for the potential reintroduction of the chestnut into the Appalachians, a third project turned to biotechnology. Research had identified oxalic acid as a key factor in the blight’s virulence. Wheat naturally produces an enzyme that degrades oxalic acid, and researchers inserted the gene that encodes that enzyme into the American chestnut genome, creating a genetically modified tree that can potentially disarm the fungus’ attack.

Without understanding the nature of resistance or the effectiveness of the transgenic gene, there’s no way to know which method would be most effective. So researchers from the American Chestnut Foundation assembled a massive collaboration to examine all these options and determine what would be needed to reintroduce blight-resistant chestnuts into the wild.

Tracking resistance

The scale of the effort is immense. All told, the team infected over 4,000 individual trees with the blight fungus and tracked their growth in Appalachian nurseries for an average of over 14 years. The trees were scored for resistance on a zero-to-100 scale based on the damage caused by the infection. This data was combined with some serious lab work; the team produced the highest-quality chestnut genomes yet (of both American and Chinese species) and gathered biochemical data on how the trees respond to infection.

It quickly became apparent that there were significant differences in the growth rates of some of the resistant trees. When planted at sites where viruses kept the blight in check, the Chinese chestnuts grew more slowly than native trees, while hybrids grew at an intermediate rate. That could make a big difference, as rapid growth may have enabled the chestnut to reach its former dominance of the canopy.

Somewhat surprisingly, this slow growth turned out to be a problem for the genetically modified American chestnuts as well. By chance, the wheat gene ended up being inserted into a gene known to be important for the growth of other plants. It seems to be important in the chestnut as well; plants with two copies of the inserted genes survived at 16 percent of their expected rate, and those with a single copy grew 22 percent slower than unmodified trees.

That said, there was a lot of variability among the genetically modified trees, with 4 percent of the tested trees showing both high blight resistance and growth comparable to that of unmodified American chestnuts. It will be important to determine whether this collection of traits remains consistent in ensuing generations.

In a bit of good news, the progeny from surviving American chestnuts grew like American chestnuts. In less good news, among 143 of these trees, only seven had resistance levels of above 50 on the team’s 100-point scale. It’s possible that interbreeding these trees could further boost resistance, but it also poses the risk of creating a population that’s too inbred to thrive after reintroduction.

Root causes

The research team decided to use their testing to investigate the genetic basis of resistance. There’s a very practical reason for this: If resistance is mediated by just a handful of genes that each have large impacts, it should be possible to continue breeding resistant strains back to regular American chestnuts and selecting for resistance. But if there are many factors with relatively small impacts, it will require directed interbreeding of hybrids to maximize both resistance and DNA originating from the American chestnut.

The team completed the highest-quality chestnut genomes for both the American and Chinese species, identifying about 25,000 to 30,000 genes in the different assemblies. They then used this information for two types of genetic analysis: quantitative trait locus identification and genome-wide association. Both approaches aim to identify regions of the genome associated with specific properties and estimate their impact.

The work suggested that resistance arises from a relatively large number of sites, each with relatively minor effects. For example, the sites in the genome identified by quantitative trait analysis typically boosted resistance by about 10 points on the researchers’ 100-point scale. In the genome-wide analysis, 17 individual genetic differences were associated with about a quarter of the heritable resistance traits. All of this suggests that, for the hybrids (and likely for the weaker blight resistance found in surviving American chestnuts), directed breeding among surviving trees will be needed.

For the root rot fungus, in contrast, it looks like there are a limited number of important alleles with a large impact.

The researchers also took an alternative approach to identify resistance factors, comparing 100 chemicals produced by resistant and susceptible strains. Among the 41 chemicals detected at higher levels in the Chinese chestnut, the researchers found a metabolite, lupeol, that completely suppressed the growth of the fungal pathogen. Another, erythrodiol, limited its growth. If we can identify the genes involved in producing those chemicals, we could use that knowledge to guide directed breeding programs—or even engage in gene editing to increase their production.

The team’s current plan is to use genomic predictions to select hybrid seedlings for planting in test orchards, aiming to identify plants with high growth and resistance. From there, the process can be repeated. But even after the exhaustive exploration of resistance traits, the researchers seem to believe that all three approaches—selecting resistant American chestnuts, breeding hybrids derived from Chinese chestnuts, and directed genetic modification—can help bring the American chestnut back.

The researchers warn, though, that as environmental disturbances and invasive species continue to push some key species to the brink of extinction, we need to get better at this kind of species rescue operation.

Science, 2026. DOI: 10.1126/science.adw3225 (About DOIs).

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Watch Kanzi the bonobo pretend to have a tea party

animal behavior, animal cognition, Biology, bonobos, primate studies, Science / Mike M. / February 5, 2026

Such studies have nonetheless been met with skepticism when it comes to interpreting the behavior as evidence of animals’ ability to engage in make-believe. For instance, it’s possible the animals are responding to behavioral cues, like the direction of a gaze, to solve such tasks.

“Kanzi, let’s play a game!”

Enter Kanzi, a 43-year-old bonobo who lives at the Ape Initiative and is capable of responding to verbal prompts, either by pointing or using a lexigram of more than 300 symbols. There had also been anecdotal observations of Kanzi engaging in pretense. Krupenye et al. conducted three distinct experiments with Kanzi, each involving an 18-trial session.

In the first experiment, a scientist would offer a verbal prompt: “Kanzi, let’s play a game! Let’s find the juice!” They would then place two empty transparent cups on a table and pretend to fill them from an empty transparent pitcher, with another verbal prompt (“Kanzi, look!”). The scientist would pretend to pour the “juice” in one of the cups back into the pitcher, placing the pitcher under the table. Then they asked, “Kanzi, where’s the juice?” and recorded which cup the bonobo pointed to first.

“If Kanzi could only track reality (that both cups were empty), he should have chosen at chance between the two options, whereas if his choices were guided by stimulus enhancement, he should have selected the incorrect cup that had been ‘emptied’ above chance,” the authors wrote. “In contrast, if Kanzi could represent the pretend juice, he should have chosen above chance the cup containing the ‘imaginary’ juice, the empty cup that had not been ‘poured’ back into the pitcher. That is exactly what Kanzi did.” Kanzi selected the correct cup 34 out of 50 times (68 percent).

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Fungus could be the insecticide of the future

biochemistry, Biology, fungus, insecticides, pine beetles, Science / Kelly Newman / February 1, 2026

Exterminators keep getting calls for a reason. Wood-devouring insects, such as beetles, termites, and carpenter ants, are constantly chewing through walls or infecting trees and breaking them down. The fight against these insects usually involved noxious insecticides; but now, at least some of them can be eliminated using a certain species of fungus.

Infestations of bark beetles are the bane of spruce trees. Eurasian spruce bark beetles (Ips typographus) ingest bark high in phenolic compounds, organic molecules that often act as antioxidants and antimicrobials. They protect spruce bark from pathogenic fungi—and the beetles take advantage. Their bodies boost the antimicrobial power of these compounds by turning them into substances that are even more toxic to fungi. This would seem to make the beetles invulnerable to fungi.

There is a way to get past the beetles’ borrowed defenses, though. Led by biochemist Ruo Sun, a team of researchers from the Max Planck Institute for Chemical Ecology in Jena, Germany, found that some strains of the fungus Beauveria bassiana are capable of infecting and killing the pests.

“Insect herbivores have long been known to accumulate plant defense metabolites from their diet as defenses against their own enemies,” she said in a study recently published in PNAS. “However, as shown here for B. bassiana, fungal pathogens are able to circumvent the toxicity of these dietary defenses and cause disease.”

First line of defense

Populations of bark beetles have recently exploded in temperate forests because of climate change. One species they feed on is the Norway spruce (Picea abies), which makes organic phenolic compounds known as stilbenes and flavonoids. Stilbenes are hydrocarbons that function as secondary metabolites for plants, and flavonoids, which are polyphenols, are also secondary plant metabolites that are often antioxidants. The spruce links both classes of compounds with sugars and relies on their antibacterial and antifungal activity.

When metabolized by the beetles, the spruce sugars are removed through hydrolysis, converting them into aglycones that are even more toxic to microscopic invaders. Despite that, some fungi appear to be able to deactivate these compounds. Strains of the fungal insect pathogen B. bassiana have been documented as killing some of these beetles in the wild.

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Meet Veronika, the tool-using cow

animal behavior, animal cognition, animal tool use, animals, Biology, Science / Beth Washington / January 19, 2026

Each time, Veronika used her tongue to lift and position the broom in her mouth, clamping down with her teeth for a stable grip. This enabled her to use the broom to scratch otherwise hard-to-reach areas on the rear half of her body. Veronika seemed to prefer the brush end to the stick end (i.e., the exploitation of distinct properties of a single object for different functions) although which end she used depended on body area. For example, she used the brush end to scratch her upper body using a scrubbing motion, while using the stick end to scratch more sensitive lower areas like her udders and belly skin flaps using precisely targeted gentle forward pushes. She also anticipated the need to adjust her grip.

The authors conclude that this behavior demonstrates “goal-directed, context-sensitive tooling,” as well as versatility in her tool-use anticipation, and fine-motor targeting. Veronika’s scratching behavior is likely motivated by the desire to relieve itching from insect bites, but her open, complex environment, compared to most livestock, and regular interactions with humans enabled her unusual cognitive abilities to emerge.

The implication is that this kind of technical problem-solving is not confined to species with large brains and hands or beaks. “[Veronika] did not fashion tools like the cow in Gary Larson’s cartoon, but she selected, adjusted, and used one with notable dexterity and flexibility,” the authors wrote. “Perhaps the real absurdity lies not in imagining a tool-using cow, but in assuming such a thing could never exist.”

DOI: Current Biology, 2025. 10.1016/j.cub.2025.11.059 (About DOIs).

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That time Will Smith helped discover new species of anaconda

anacondas, Biology, culture, Disney Plus, National Geographic, Science, Taxonomy, zoology / Kelly Newman / January 11, 2026

In 2024, scientists announced the discovery of a new species of giant anaconda in South America. A National Geographic camera crew was on hand for the 2022 expedition that documented the new species—and so was actor Will Smith, since they were filming for NatGeo’s new documentary series, Pole to Pole with Will Smith. Now we can all share in Smith’s Amazon experience, courtesy of the three-minute clip above.

Along with venom expert Bryan Fry, we follow Smith’s journey by boat with a team of indigenous Waorani guides, scouring the river banks for anacondas. And they find one: a female green anaconda about 16 to 17 feet long, “pure muscle.” The Waorani secure the giant snake—anacondas aren’t venomous but they do bite—so that Fry (with Smith’s understandably reluctant help) can collect a scale sample for further analysis. Fry says that this will enable him to determine the accumulation of pollutants in the water.

That and other collected samples also enabled scientists to conduct the genetic analysis that resulted in the declaration of a new species: the northern green anaconda (Eunectes akayama, which roughly translates to “the great snake”). It is genetically distinct from the southern green anaconda (Eunectes murinus); the two species likely diverged some 10 million years ago. The northern green anaconda’s turf includes Venezuela, Colombia, Suriname, French Guyana, and the northern part of Brazil.

Local Waorani guides subdue a giant green anaconda YouTube/National Geographic

Smith’s time in the Amazon also brought the arachnophobic actor face to face with a giant tarantula while scientists extracted the venom. His further adventures brought him to the South Pole, where he trekked across frigid ice fields; to the Himalayas, where he trekked to a small village in Bhutan; to the Pacific Islands to record a lost native language; to the Kalahari desert, where he joined the hunter-gatherer San people on a hunt; and to the North Pole, where he joined an expedition to dive under the ice to collect scientific samples.

Pole to Pole with Will Smith premieres on January 13, 2026, and will stream on Disney+ the following day.

poster art showing bearded will smith in a parka with snow crystallizing on his beard — Credit: National Geographic

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Looking for friends, lobsters may stumble into an ecological trap

Biology, evolution, groupers, lobsters, ocean science, Science / DJ Henderson / December 30, 2025

The authors, Mark Butler, Donald Behringer, and Jason Schratwieser, hypothesized that these solution holes represent an ecological trap. The older lobsters that find shelter in a solution hole would emit the chemicals that draw younger ones to congregate with them. But the youngsters would then fall prey to any groupers that inhabit the same solution hole. In other words, what is normally a cue for safety—the signal that there are lots of lobsters present—could lure smaller lobsters into what the authors call a “predatory death trap.”

Testing the hypothesis involved a lot of underwater surveys. First, the authors identified solution holes with a resident red grouper. They then found a series of sites that had equivalent amounts of shelter, but lacked the solution hole and attendant grouper. (The study lacked a control with a solution hole but no grouper, for what it’s worth.) At each site, the researchers started daily surveys of the lobsters present, registering how large they were and tagging any that hadn’t been found in any earlier surveys. This let them track the lobster population over time, as some lobsters may migrate in and out of sites.

To check predation, they linked lobsters (both large and small) via tethers that let them occupy sheltered places on the sea floor, but not leave a given site. And, after the lobster population dynamics were sorted, the researchers caught some of the groupers and checked their stomach contents. In a few cases, this revealed the presence of lobsters that had been previously tagged, allowing them to directly associate predation with the size of the lobster.

Lobster traps

So, what did they find? In sites where groupers were present, the average lobster was 32 percent larger than the control sites. That’s likely to be because over two-thirds of the small lobsters that were tethered to sites with a grouper were dead within 48 hours. At control sites, the mortality rate was about 40 percent. That’s similar to the mortality rates for larger lobsters at the same sites (44 percent) or at sites with groupers (48 percent).

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The evolution of expendability: Why some ants traded armor for numbers

ants, Biology, evolution, Science / Mike M. / December 19, 2025

“Ants reduce per-worker investment in one of the most nutritionally expensive tissues for the good of the collective,” Matte explains. “They’re shifting from self-investment toward a distributed workforce.”

Power of the collective

The researchers think the pattern they observed in ants reflects a more universal trend in the evolution of societal complexity. The transition from solitary life to complex societies echoes the transition from single-celled organisms to multicellular ones.

In a single-celled organism, a cell must be a “jack-of-all-trades,” performing every function necessary for survival. In a multicellular animal, however, individual cells often become simpler and more specialized, relying on the collective for protection and resources.

“It’s a pattern that echoes the evolution of multicellularity, where cooperative units can be individually simpler than a solitary cell, yet collectively capable of far greater complexity,” says Matte. Still, the question of whether underinvesting in individuals to boost the collective makes sense for creatures other than ants remains open, and it most likely isn’t as much about nutritional economics as it is about sex.

Expendable servants

The study focused on ants that already have a reproductive division of labor, one where workers do not reproduce. This social structure is likely the key prerequisite for the cheap worker strategy. For the team, this is the reason we haven’t, at least so far, found similar evolutionary patterns in more complex social organisms like wolves, which live in packs—or humans with their amazingly complex societies. Wolves and people are both social, but maintain a high degree of individual self-interest regarding reproduction. Ant workers could be made expendable because they don’t pass their own genes—they are essentially extensions of the queen’s reproductive strategy.

Before looking for signs of ant-like approaches to quality versus quantity dilemmas in other species, the team wants to take an even closer look at ants. Economo, Matte, and their colleagues seek to expand their analysis to other ant tissues, such as the nervous system and muscles, to see if the cheapening of individuals extends beyond the exoskeleton. They are also looking at ant genomes to see what genetic innovations allowed for the shift from quality to quantity. “We still need a lot of work to understand ants’ evolution,” Matte says.

Science Advances. 2025. DOI: 10.1126/sciadv.adx8068

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Welcome to “necroprinting”—3D printer nozzle made from mosquito’s proboscis

3D printing, Biology, Biomechanics, materials science, mosquitos, printing, Science / Kelly Newman / December 4, 2025

“To integrate the proboscis, we first removed it from an already euthanized mosquito under a microscope,” Cao explains. Then the proboscis/nozzle was aligned with the outlet of the plastic tip. Finally, the proboscis and the tip were bonded with UV-curable resin.

The necroprinter achieved a resolution ranging from 18 to 22 microns, which was two times smaller than the printers using the smallest commercially available metal dispensing tips. The first print tests included honeycomb structures measuring 600 microns, a microscale maple leaf, and scaffolds for cells.

But there were still areas in which human-made technology managed to beat Mother Nature.

Glass and pressure

The first issue with mosquito nozzles was their relatively low resistance to internal pressure. “It was impressive but still too low to accommodate some high viscosity inks,” Cao said.

These inks, which look more like a paste than a typical fluid, hold shape better, which translates into more geometrically accurate models that do not slump or spread under their own weight. This was a problem that Cao’s test prints experienced to an extent.

But this wasn’t the only area where human-made technology managed to beat nature. While mosquito nozzles could outperform plastic or metal alternatives in precision, they could not outperform glass dispensing tips, which can print lines below one micron across and withstand significantly higher pressures.

The researchers already have some ideas about how to bridge at least a part of this gap, though. “One possible solution is to use mosquito proboscis as the core and coat it with ceramic layers to provide much higher strength,” Cao said. And if the pressure problem is solved, the 18–22 microns resolution should be good enough for plenty of things.

Cao thinks that in the future, printers like this could be used to print scaffolds for living cells or microscopic electronic components. The idea is to replace expensive, traditional 3D printing nozzles with more affordable organic counterparts. The key advantages of mosquito nozzles, he says, are low cost and ubiquity.

Mosquitoes live almost everywhere on Earth and are easy to rear. The team estimates that organic 3D printing nozzles made from mosquito proboscises should cost around 80 cents; the glass and metal alternatives, the researchers state in the paper, cost between 32 and 100 times more.

“We already started doing more research on mosquitoes themselves and hope to develop more engineering solutions, not only to leverage their deceased bodies but also to solve practical problems they cause,” Cao said.

Science Advances, 2025. DOI: 10.1126/sciadv.adw9953

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Research roundup: 6 cool stories we almost missed

animals, Biology, chemistry, fermentation, microbiology, Physics, psychology, robotics, Science, social networks / DJ Henderson / December 1, 2025

The assassination of a Hungarian duke, why woodpeckers grunt when they peck, and more.

Skull of remains found in a 13th century Dominican monastery on Margaret Island, Budapest, Hungary Credit: Eötvös Loránd University

It’s a regrettable reality that there is never enough time to cover all the interesting scientific stories we come across each month. In the past, we’ve featured year-end roundups of cool science stories we (almost) missed. This year, we’re experimenting with a monthly collection. November’s list includes forensic details of the medieval assassination of a Hungarian duke, why woodpeckers grunt when they peck, and more evidence that X’s much-maligned community notes might actually help combat the spread of misinformation after all.

An assassinated medieval Hungarian duke

The observed perimortem lesions on the human remains (CL=cranial lesion, PL= Postcranial lesion). The drawing of the skeleton was generated using OpenAI’s image generation tools (DALL·E) via ChatGPT. — Credit: Tamás Hajdu et al., 2026

Back in 1915, archaeologists discovered the skeletal remains of a young man in a Dominican monastery on Margaret Island in Budapest, Hungary. The remains were believed to be those of Duke Bela of Masco, grandson of the medieval Hungarian King Bela IV. Per historical records, the young duke was brutally assassinated in 1272 by a rival faction and his mutilated remains were recovered by the duke’s sister and niece and buried in the monastery.

The identification of the remains was based on a contemporary osteological analysis, but they were subsequently lost and only rediscovered in 2018. A paper published in the journal Forensic Science International: Genetics has now confirmed that identification and shed more light on precisely how the duke died. (A preprint is available on bioRxiv.]

An interdisciplinary team of researchers performed various kinds of bioarchaeological analysis on the remains. including genetic testing, proteomics, 3D modeling, and radiocarbon dating. The resulting data definitively proves that the skeleton is indeed that of Duke Bela of Masco.

The authors were also able to reconstruct the manner of the duke’s death, concluding that this was a coordinated attack by three people. One attacked from the front while the other two attacked from the left and right sides, and the duke was facing his assassins and tried to defend himself. The weapons used were most likely a saber and a long sword, and the assassins kept raining down blows even after the duke had fallen to the ground. The authors concluded that while the attack was clearly planned, it was also personal and fueled by rage or hate.

DOI: Forensic Science International: Genetics, 2025. 10.1016/j.fsigen.2025.103381 (About DOIs).

Why woodpeckers grunt when they peck

A male Pileated woodpecker foraging on a t

Woodpeckers energetically drum away at tree trunks all day long with their beaks and yet somehow never seem to get concussions, despite the fact that such drumming can produce deceleration forces as high as 1,200 g’s. (Humans suffer concussions with a sudden deceleration of just 100 g’s.) While popular myth holds that woodpecker heads are structured in such a way to absorb the shock, and there has been some science to back that up, more recent research found that their heads act more like hammers than shock absorbers. A paper published in the Journal of Experimental Biology sheds further light on the biomechanics of how woodpeckers essentially turn themselves into hammers and reveals that the birds actually grunt as they strike wood.

The authors caught eight wild downy woodpeckers and recorded them drilling and tapping on pieces of hardwood in the lab for three days, while also measuring electrical signals in their heads, necks, abdomens, tails, and leg muscles. Analyzing the footage, they found that woodpeckers use their hip flexors and front neck muscles to propel themselves forward as they peck while tipping their heads back and bracing themselves using muscles at the base of the skull and back of the neck. The birds use abdominal muscles for stability and brace for impact using their tail muscles to anchor their bodies against a tree. As for the grunting, the authors noted that it’s a type of breathing pattern used by tennis players (and martial artists) to boost the power of a strike.

DOI: Journal of Experimental Biology, 2025. 10.1242/jeb.251167 (About DOIs).

Raisins turn water into wine

wine glass half filled with raisins — Credit: Kyoto University

Fermentation has been around in some form for millennia, relying on alcohol-producing yeasts like Saccharomyces cerevisiae; cultured S. cerevisiae is still used by winemakers today. It’s long been thought that winemakers in ancient times stored fresh crushed grapes in jars and relied on natural fermentation to work its magic, but recent studies have called this into question by demonstrating that S. cerevisiae colonies usually don’t form on fresh grape skins. But the yeast does like raisins, as Kyoto University researchers recently discovered. They’ve followed up that earlier work with a paper published in Scientific Reports, demonstrating that it’s possible to use raisins to turn water into wine.

The authors harvested fresh grapes and dried them for 28 days. Some were dried using an incubator, some were sun-dried, and a third batch was dried using a combination of the two methods. The researchers then added the resulting raisins to bottles of water—three samples for each type of drying process—sealed the bottles, and stored them at room temperature for two weeks. One incubator-dried sample and two combo samples successfully fermented, but all three of the sun-dried samples did so, and at higher ethanol concentrations. Future research will focus on identifying the underlying molecular mechanisms. And for those interested in trying this at home, the authors warn that it only works with naturally sun-dried raisins, since store-bought varieties have oil coatings that block fermentation.

DOI: Scientific Reports, 2025. 10.1038/s41598-025-23715-3 (About DOIs).

An octopus-inspired pigment

An octopus camouflages itself with the seafloor. — Credit: Charlotte Seid

Octopuses, cuttlefish, and several other cephalopods can rapidly shift the colors in their skin thanks to that skin’s unique complex structure, including layers of chromatophores, iridophores, and leucophores. A color-shifting natural pigment called xanthommatin also plays a key role, but it’s been difficult to study because it’s hard to harvest enough directly from animals, and lab-based methods of making the pigment are labor-intensive and don’t yield much. Scientists at the University of San Diego have developed a new method for making xanthommatin in substantially larger quantities, according to a paper published in Nature Biotechnology.

The issue is that trying to get microbes to make foreign compounds creates a metabolic burden, and the microbes hence resist the process, hindering yields. The USD team figured out how to trick the cells into producing more xanthommatin by genetically engineering them in such a way that making the pigment was essential to a cell’s survival. They achieved yields of between 1 and 3 grams per liter, compared to just five milligrams of pigment per liter using traditional approaches. While this work is proof of principle, the authors foresee such future applications as photoelectronic devices and thermal coatings, dyes, natural sunscreens, color-changing paints, and environmental sensors. It could also be used to make other kinds of chemicals and help industries shift away from older methods that rely on fossil fuel-based materials.

DOI: Nature Biotechnology, 2025. 10.1038/s41587-025-02867-7 (About DOIs).

A body-swap robot

Participant standing on body-swap balance robot — Credit: Sachi Wickramasinghe/UBC Media Relations

Among the most serious risks facing older adults is falling. According to the authors of a paper published in Science Robotics, standing upright requires the brain to coordinate signals from the eyes, inner ears, and feet to counter gravity, and there’s a natural lag in how fast this information travels back and forth between brain and muscles. Aging and certain diseases like diabetic neuropathy and multiple sclerosis can further delay that vital communication; the authors liken it to steering a car with a wheel that responds half a second late. And it’s a challenge to directly study the brain under such conditions.

That’s why researchers at the University of British Columbia built a large “body swap” robotic platform. Subjects stood on force plates attached to a motor-driven backboard to reproduce the physical forces at play when standing upright: gravity, inertia, and “viscosity,” which in this case describes the damping effect of muscles and joints that allow us to lean without falling. The platform is designed to subtly alter those forces and also add a 200-millisecond delay.

The authors tested 20 participants and found that lowering inertia and making the viscosity negative resulted in similar instability to that which resulted from a signal delay. They then brought in ten new subjects to study whether adjusting body mechanics could compensate for information delays. They found that adding inertia and viscosity could at least partially counter the instability that arose from signal delay—essentially giving the body a small mechanical boost to help the brain maintain balance. The eventual goal is to design wearables that offer gentle resistance when an older person starts to lose their balance, and/or help patients with MS, for example, adjust to slower signal feedback.

DOI: Science Robotics, 2025. 10.1126/scirobotics.adv0496 (About DOIs).

X community notes might actually work

cropped image of phone screen showing an X post with a community note underneath — Credit: Huaxia Rui

Earlier this year, Elon Musk claimed that X’s community notes feature needed tweaking because it was being gamed by “government & legacy media” to contradict Trump—despite vigorously defending the robustness of the feature against such manipulation in the past. A growing body of research seems to back Musk’s earlier stance.

For instance, last year Bloomberg pointed to several studies suggesting that crowdsourcing worked just as well as using professional fact-checkers when assessing the accuracy of news stories. The latest evidence that crowd-sourcing fact checks can be effective at curbing misinformation comes from a paper published in the journal Information Systems Research, which found that X posts with public corrections were 32 percent more likely to be deleted by authors.

Co-author Huaxia Rui of the University of Rochester pointed out that community notes must meet a threshold before they will appear publicly on posts, while those that do not remain hidden from public view. Seeing a prime opportunity in the arrangement, Rui et al. analyzed 264,600 X posts that had received at least one community note and compared those just above and just below that threshold. The posts were collected from two different periods: June through August 2024, right before the US presidential election (when misinformation typically surges), and the post-election period of January and February 2025.

The fact that roughly one-third of authors responded to public community notes by deleting the post suggests that the built-in dynamics of social media (e.g., status, visibility, peer feedback) might actually help improve the spread of misinformation as intended. The authors concluded that crowd-checking “strikes a balance between First Amendment rights and the urgent need to curb misinformation.” Letting AI write the community notes, however, is probably still a bad idea.

DOI: Information Systems Research, 2025. 10.1287/isre.2024.1609 (About DOIs).

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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Many genes associated with dog behavior influence human personalities, too

Behavioral science, Biology, Dogs, Genetics, Genomics, golden retrievers, Science / Beth Washington / November 26, 2025

Many dog breeds are noted for their personalities and behavioral traits, from the distinctive vocalizations of huskies to the herding of border collies. People have worked to identify the genes associated with many of these behaviors, taking advantage of the fact that dogs can interbreed. But that creates its own experimental challenges, as it can be difficult to separate some behaviors from physical traits distinctive to the breed—small dog breeds may seem more aggressive simply because they feel threatened more often.

To get around that, a team of researchers recently did the largest gene/behavior association study within a single dog breed. Taking advantage of a population of over 1,000 golden retrievers, they found a number of genes associated with behaviors within that breed. A high percentage of these genes turned out to correspond to regions of the human genome that have been associated with behavioral differences as well. But, in many cases, these associations have been with very different behaviors.

Gone to the dogs

The work, done by a team based largely at Cambridge University, utilized the Golden Retriever Lifetime Study, which involved over 3,000 owners of these dogs filling out annual surveys that included information on their dogs’ behavior. Over 1,000 of those owners also had blood samples obtained from their dogs and shipped in; the researchers used these samples to scan the dogs’ genomes for variants. Those were then compared to ratings of the dogs’ behavior on a range of issues, like fear or aggression directed toward strangers or other dogs.

Using the data, the researchers identified when different regions of the genome were frequently associated with specific variants. In total, 14 behavioral tendencies were examined, and 12 genomic regions were associated with specific behaviors, and another nine showed somewhat weaker associations. For many of these traits, it was difficult to find much because golden retrievers are notoriously friendly and mellow dogs, so they tended to score low on traits like aggression and fear.

That result was significant, as some of these same regions of the genome had been associated with very different behaviors in populations that were a mix of breeds. For example, two different regions associated with touch sensitivity in golden retrievers had been linked to a love of chasing and owner-directed aggression in a non-breed-specific study. That finding suggests that the studies were identifying genes that may be involved in setting the stage for behaviors, but were directed into specific outcomes by other genetic or environmental factors.

Many genes associated with dog behavior influence human personalities, too Read More »

AI trained on bacterial genomes produces never-before-seen proteins

AI, bacteria, Biology, Computer science, evolution, Genomics, large language model, Science / 9u50fv / November 22, 2025

The researchers argue that this setup lets Evo “link nucleotide-level patterns to kilobase-scale genomic context.” In other words, if you prompt it with a large chunk of genomic DNA, Evo can interpret that as an LLM would interpret a query and produce an output that, in a genomic sense, is appropriate for that interpretation.

The researchers reasoned that, given the training on bacterial genomes, they could use a known gene as a prompt, and Evo should produce an output that includes regions that encode proteins with related functions. The key question is whether it would simply output the sequences for proteins we know about already, or whether it would come up with output that’s less predictable.

Novel proteins

To start testing the system, the researchers prompted it with fragments of the genes for known proteins and determined whether Evo could complete them. In one example, if given 30 percent of the sequence of a gene for a known protein, Evo was able to output 85 percent of the rest. When prompted with 80 percent of the sequence, it could return all of the missing sequence. When a single gene was deleted from a functional cluster, Evo could also correctly identify and restore the missing gene.

The large amount of training data also ensured that Evo correctly identified the most important regions of the protein. If it made changes to the sequence, they typically resided in the areas of the protein where variability is tolerated. In other words, its training had enabled the system to incorporate the rules of evolutionary limits on changes in known genes.

So, the researchers decided to test what happened when Evo was asked to output something new. To do so, they used bacterial toxins, which are typically encoded along with an anti-toxin that keeps the cell from killing itself whenever it activates the genes. There are a lot of examples of these out there, and they tend to evolve rapidly as part of an arms race between bacteria and their competitors. So, the team developed a toxin that was only mildly related to known ones, and had no known antitoxin, and fed its sequence to Evo as a prompt. And this time, they filtered out any responses that looked similar to known antitoxin genes.

AI trained on bacterial genomes produces never-before-seen proteins Read More »