Mother’s Day is on my mind, and I’ve been thinking about the ways I’m connected to my mom and my two little daughters. Every so often I see flickers of my mom in my girls — they share the lines around their smiles and a mutual adoration of wildflowers. Of course, I’m biased. I know that I’m seeing what I’m looking for. But biologically speaking, mothers and their children are connected in a way that may surprise you.

Way back when you and your mom shared a body, your cells mingled. Her cells slipped into your body and your cells circled back into her. This process, called fetal-maternal microchimerism, turns both mother and child into chimeras harboring little pieces of each other.

Cells from my daughters are knitted into my body and bones and brain. I also carry cells from my mom, and quite possibly from my grandma. I may even harbor cells from my older brother, who may have given some cells to my mom, who then gave them to me. It means my younger brother just might have cells from all of us, poor guy. This boundary blurring invites some serious existential wonder, not least of which might involve you wondering if this means your family members really are in your head.

These cellular threads tie families together in ways that scientists are just starting to discover. Here are a few of my favorite instances of how cells from a child have woven themselves into a mother’s body:
Fetal cells are probably sprinkled throughout a mother’s brain. A study of women who had died in their 70s found that over half of the women had male DNA (a snippet from the Y chromosome) in their brains, presumably from when their sons were in the womb. Scientists often look for male DNA in women because it’s easier than distinguishing a daughter’s DNA from her mother’s. If DNA from daughters were included, the number of women with children’s cells in their brains would probably be even higher.

When the heart is injured, fetal cells seem to flock to the site of injury and turn into several different types of specialized heart cells. Some of these cells may even start beating, a mouse study found. So technically, those icky-sweet Mother’s Day cards may be right: A mother really does hold her children in her heart.

Fetal cells circulate in a mother’s blood. Male DNA turned up in blood samples from women who were potential stem cell donors. That result may have implications for stem cell transplants. This cell swapping may make parents better donor candidates for their children than strangers, for instance.
Other studies have found fetal cells in a mother’s bones, liver, lungs and other organs, suggesting that these cells have made homes for themselves throughout a mother’s body. Maybe this is a way for a child to give back to the mother, in a sense. Growing fetuses slurp nutrients and energy out of a mother’s body during pregnancy (not to mention the morning sickness, heartburn and body aches). In return, fetuses offer up these young, potentially helpful cells. Perhaps these fetal cells, which may possess the ability to turn into lots of different kinds of cells, can help repair a damaged heart, liver or thyroid, as some studies have hinted.

Before I get carried away, a caveat: these cells may also make mischief. They may have a role in autoimmune disorders, for instance.

Microchimerism also has implications here for women who have lost pregnancies, an extremely common situation hidden by the taboo of talking about miscarriages. Fetal cells seem to migrate early in pregnancy, meaning that even brief pregnancies may leave a cellular mark on a woman.

Scientists are just starting to discover how this cellular heritage works, and how it might influence health. The scientist in me can’t wait to see how this story unfolds. But for now, I’m content to marvel at the mother and daughters in me.

A zap to the head can stretch the time between intention and action, a new study finds. The results help illuminate how intentions arise in the brain.

The study, published in the May 6 Journal of Neuroscience, “provides fascinating new clues” about the process of internal decision making, says neuroscientist Gabriel Kreiman of Harvard University. These sorts of studies are bringing scientists closer to “probing some of the fundamental questions about who we are and why we do what we do,” he says.
Figuring out how the brain generates a sense of control may also have implications for people who lack those feelings. People with alien hand syndrome, psychogenic movement disorders and schizophrenia can experience a troubling disconnect between intention and action, says study coauthor Biyu Jade He of the National Institutes of Health in Bethesda, Md.

In the study, the researchers manipulated people’s intentions without changing their actions. The researchers told participants to click a mouse whenever the urge struck. Participants estimated when their intention to click first arose by monitoring a dot’s position on a clockface.

Intention to click usually preceded the action by 188 milliseconds on average, the team found. But a session of transcranial direct current stimulation, or tDCS, moved the realization of intention even earlier, stretching time out between awareness of intention and the action. tDCS electrodes delivered a mild electrical zap to participants’ heads, dialing up the activity of carefully targeted nerve cells. After stimulation, intentions arrived about 60 to 70 milliseconds sooner than usual. tDCS seemed to change certain kinds of brain activity that may have influenced the time shift, EEG recordings suggested.

The results highlight how thoughts and intentions can be separated from the action itself, a situation that appears to raise thorny questions about free will. But these tDCS zaps didn’t change the action outcome or participants’ feelings of control, only the reported timing of a person’s conscious intention.

MONTREAL — For the first time, scientists have precisely captured a map of the boisterous bang radiating from a lightning strike. The work could reveal the energies involved in powering some of nature’s flashiest light shows.

As electric current rapidly flows from a negatively charged cloud to the ground below, the lightning rapidly heats and expands the surrounding air, generating sonic shock waves. While scientists have a basic understanding of thunder’s origins, they lack a detailed picture of the physics powering the crashes and rumbles.
Heliophysicist Maher Dayeh of the Southwest Research Institute in San Antonio and colleagues sparked their own lightning by firing a long, Kevlar-coated copper wire into an electrically charged cloud using a small rocket. The resulting lightning followed the conductive wire to the ground. Using 15 sensitive microphones laid out 95 meters from the strike zone, Dayeh said he and his colleagues precisely recorded the incoming sound waves. Because sound waves from higher elevations took longer to reach the microphones, the scientists could create an acoustic map of the lightning strike with “surprising detail,” Dayeh said. He presented the results May 5 at a meeting of the American Geophysical Union and other organizations.

The loudness of a thunderclap depends on the peak electric current flowing through the lightning, the researchers found. This discovery could one day allow scientists to use thunder to sound out the amount of energy powering a lightning strike, Dayeh said.
SHOCK AND AWE Scientists shot a long copper wire into a lightning-prone cloud using a small rocket. The generated lightning followed the wire down to the ground, allowing the researchers to record the sound waves of the resulting thunder. The green flashes are caused by the intense heating of the copper wire. Credit: Univ. of Florida, Florida Institute of Technology, SRI

A new high-tech glove totally sucks — and that’s a good thing.

Each fingertip is outfitted with a sucker inspired by those on octopus arms. These suckers allow people to grab slippery, underwater objects without squeezing too tightly, researchers report July 13 in Science Advances.

“Being able to grasp things underwater could be good for search and rescue, it could be good for archaeology, [and] could be good for marine biology,” says mechanical engineer Michael Bartlett of Virginia Tech in Blacksburg.
Each sucker on the glove is a raspberry-sized rubber cone capped with a thin, stretchy rubber sheet. Vacuuming the air out of a sucker pulls its cap into a concave shape that sticks to surfaces like a suction cup. Pumping air back into the sucker inflates its cap, causing it to pop off surfaces. Each finger is also equipped with a Tic Tac–sized sensor that detects nearby surfaces. When the sensor comes within some preset distance of any object, it switches the sucker on that finger to sticky mode.

Bartlett and colleagues used the glove to pick up objects underwater, including a toy car, plastic spoon and metal bowl. Each sucker could lift about one kilogram in open air — and could lift more underwater, with the help of buoyancy, Bartlett says. Adding more suckers could give the glove an even stronger grip.
The octopus-inspired glove barely brushes the surface of what octopuses and other cephalopods can do. Octopuses can individually control thousands of suckers across their eight arms to feel around the seafloor and snatch prey. The suckers do this using not only tactile sensors, but also chemical-detecting cells that “taste” their surroundings (SN: 10/29/20).

The new glove is far from turning fingers into extra tongues. But Bartlett is intrigued by the possibility of adding chemical sensors so that the suckers stick to only certain materials.

Humans have long tried to wrangle water. We’ve straightened once-meandering rivers for shipping purposes. We’ve constructed levees along rivers and lakes to protect people from flooding. We’ve erected entire cities on drained and filled-in wetlands. We’ve built dams on rivers to hoard water for later use.

“Water seems malleable, cooperative, willing to flow where we direct it,” environmental journalist Erica Gies writes in Water Always Wins. But it’s not, she argues.

Levees, which narrow channels causing water to flow higher and faster, nearly always break. Cities on former wetlands flood regularly — often catastrophically. Dams starve downstream environs of sediment needed to protect coastal areas against rising seas. Straightened streams flow faster than meandering ones, scouring away riverbed ecosystems and giving water less time to seep downward and replenish groundwater supplies.

In addition to laying out this damage done by supposed water control, Gies takes readers on a hopeful global tour of solutions to these woes. Along the way, she introduces “water detectives”— scientists, engineers, urban planners and many others who, instead of trying to control water, ask: What does water want?
These water detectives have found ways to give the slippery substance the time and space it needs to trickle underground. Around Seattle’s Thornton Creek, for instance, reclaimed land now allows for regular flooding, which has rejuvenated depleted riverbed habitat and created an urban oasis. In California’s Central Valley, scientists want to find ways to shunt unpolluted stormwater into ancient, sediment-filled subsurface canyons that make ideal aquifers. Feeding groundwater supplies will in turn nourish rivers from below, helping to maintain water levels and ecosystems.

While some people are exploring new ways to manage water, others are leaning on ancestral knowledge. Without the use of hydrologic mapping tools, Indigenous peoples of the Andes have a detailed understanding of the plumbing that links surface waters with underground storage. Researchers in Peru are now studying Indigenous methods of water storage, which don’t require dams, in hopes of ensuring a steady flow of water to Lima — Peru’s populous capital that’s periodically afflicted by water scarcity. These studies may help convince those steeped in concrete-centric solutions to try something new. “Decision makers come from a culture of concrete,” Gies writes, in which dams, pipes and desalination plants are standard.

Understanding how to work with, not against, water will help humankind weather this age of drought and deluge that’s being exacerbated by climate change. Controlling water, Gies convincingly argues, is an illusion. Instead, we must learn to live within our water means because water will undoubtedly win.

Pocket gophers certainly don’t qualify as card-carrying 4-H members, but the rodents might be farming roots in the open air of their moist, nutrient-rich tunnels.

The gophers subsist mostly on roots encountered in the tunnels that the rodents excavate. But the local terrain doesn’t always provide enough roots to sustain gophers, two researchers report in the July 11 Current Biology. To make up the deficit, the gophers practice a simple type of agriculture by creating conditions that promote more root growth, suggest ecologist Jack Putz of the University of Florida in Gainesville and his former zoology undergraduate student Veronica Selden.
But some scientists think it’s a stretch to call the rodents’ activity farming. Gophers aren’t actively working the soil, these researchers say, but inadvertently altering the environment as the rodents eat and poop their way around — much like all animals do.

Tunnel digging takes a lot of energy — up to 3,400 times as much as walking along the surface for gophers. To see how the critters were getting all this energy, Selden and Putz in 2021 began investigating the tunnels of southeastern pocket gophers (Geomys pinetis) in an area being restored to longleaf pine savanna in Florida that Putz partially owns.

The pair took root samples from soil adjacent to 12 gopher tunnels and extrapolated how much root mass a gopher would encounter as it excavated a meter of tunnel. Then the researchers calculated the amount of energy that those roots would provide.

“We were able to compare energy cost versus gain, and found that on average there is a deficit, with about half the cost of digging being unaccounted for,” Selden says.

Upon examining some tunnels, Selden and Putz saw gopher feces spread through the interior along with signs of little bites taken out of roots and churning of the soil.

The gophers, the researchers conclude, provide conditions that favor root growth by spreading their own waste as fertilizer, aerating the soil and repeatedly nibbling on roots to encourage new sprouting.

“All of these activities encourage root growth, and once the roots grow into the tunnels, the gophers crop the roots,” Selden says. She and Putz say that this amounts to a rudimentary form of farming. If so, gophers would be the first nonhuman mammals to be recognized as farmers, Putz says. Other organisms, such as some insects, also farm food and started doing so much earlier than humans (SN: 4/23/20).

But the study has its skeptics. “I don’t really think you can call it farming per the human definition. All herbivores eat plants, and everybody poops,” says J.T. Pynne, a wildlife biologist at the Georgia Wildlife Federation in Covington who studies southeastern pocket gophers. So the root nibbling and tunnel feces might not be signs of agriculture, just gophers doing what all animals do.

Evolutionary biologist Ulrich Mueller agrees. “If we accept the tenuous evidence presented in the Selden article as evidence for farming … then most mammals and most birds are farmers because each of them accidentally have also some beneficial effects on some plants that these mammals or birds also feed on,” he says.

Not only that, but the study is also dangerous, says Mueller, of the University of Texas at Austin. The public will see through “the shallowness of the data,” he says, and will conclude that science is “just a bunch of storytelling, eroding general trust in science.”

For her part, Selden says she understands that because gophers don’t plant their crops, not everyone is comfortable calling them farmers. Still, she argues that “what qualifies the gophers as farmers and sets them apart from, say, cattle, which incidentally fertilize the grass they eat with their wastes, is that gophers cultivate and maintain this ideal environment for roots to grow into.”

At the very least, Putz says, he hopes their research makes people kinder toward the rodents. “If you go to the web and put in ‘pocket gopher,’ you’ll see more ways to kill them than you can count.”

In the beginning, scientists believe there was an interstellar gas cloud of all the elements comprising the Earth. A billion or so years later, the Earth was a globe of concentric spheres with a solid iron inner core, a liquid iron outer core and a liquid silicate mantle…. The current theory is that the primeval cloud’s materials accreted … and that sometime after accretion, the iron, melted by radioactive heating, sank toward the center of the globe…. Now another concept is gaining ground: that the Earth may have accreted … with core formation and accretion occurring simultaneously.

Update
Most scientists now agree that the core formed as materials that make up Earth collided and glommed together and that the process was driven by heat from the smashups. The planet’s heart is primarily made of iron, nickel and some oxygen, but what other elements may dwell there and in what forms remains an open question. Recently, scientists proposed the inner core could be superionic, with liquid hydrogen flowing through an iron and silicon lattice (SN: 3/12/22, p. 12).

If every mineral tells a story, then geologists now have their equivalent of The Arabian Nights.

For the first time, scientists have cataloged every different way that every known mineral can form and put all of that information in one place. This collection of mineral origin stories hints that Earth could have harbored life earlier than previously thought, quantifies the importance of water as the most transformative ingredient in geology, and may change how researchers look for signs of life and water on other planets.
“This is just going to be an explosion,” says Robert Hazen, a mineralogist and astrobiologist at the Carnegie Institution for Science in Washington, D.C. “You can ask a thousand questions now that we couldn’t have answered before.”

For over 100 years, scientists have defined minerals in terms of “what,” focusing on their structure and chemical makeup. But that can make for an incomplete picture. For example, though all diamonds are a kind of crystalline carbon, three different diamonds might tell three different stories, Hazen says. One could have formed 5 billion years ago in a distant star, another may have been born in a meteorite impact, and a third could have been baked deep below the Earth’s crust.
So Hazen and his colleagues set out to define a different approach to mineral classification. This new angle focuses on the “how” by thinking about minerals as things that evolve out of the history of life, Earth and the solar system, he and his team report July 1 in a pair of studies in American Mineralogist. The researchers defined 57 main ways that the “mineral kingdom” forms, with options ranging from condensation out of the space between stars to formation in the excrement of bats.

The information in the catalog isn’t new, but it was previously scattered throughout thousands of scientific papers. The “audacity” of their work, Hazen says, was to go through and compile it all together for the more than 5,600 known types of minerals. That makes the catalog a one-stop shop for those who want to use minerals to understand the past.

The compilation also allowed the team to take a step back and think about mineral evolution from a broader perspective. Patterns immediately popped out. One of the new studies shows that over half of all known mineral kinds form in ways that ought to have been possible on the newborn Earth. The implication: Of all the geologic environments that scientists have considered as potential crucibles for the beginning of life on Earth, most could have existed as early as 4.3 billion years ago (SN: 9/24/20). Life, therefore, may have formed almost as soon as Earth did, or at the very least, had more time to arise than scientists have thought. Rocks with traces of life date to only 3.4 billion years ago (SN: 7/26/21).

“That would be a very, very profound implication — that the potential for life is baked in at the very beginning of a planet,” says Zachary Adam, a paleobiologist at the University of Wisconsin–Madison who was not involved in the new studies.

The exact timing of when conditions ripe for life arose is based on “iffy” models, though, says Frances Westall, a geobiologist at the Center for Molecular Biophysics in Orléans, France, who was also not part of Hazen’s team. She thinks that scientists need more data before they can be sure. But, she says, “the principle is fantastic.”

The new results also show how essential water has been to making most of the minerals on Earth. Roughly 80 percent of known mineral types need H2O to form, the team reports.

“Water is just incredibly important,” Hazen says, adding that the estimate is conservative. “It may be closer to 90 percent.”
Taken one way, this means that if researchers see water on a planet like Mars, they can guess that it has a rich mineral ecosystem (SN: 3/16/21). But flipping this idea may be more useful: Scientists could identify what minerals are on the Red Planet and then use the new catalog to work backward and figure out what its environment was like in the past. A group of minerals, for example, might be explainable only if there had been water, or even life.

Right now, scientists do this sort of detective work on just a few minerals at a time (SN: 5/11/20). But if researchers want to make the most of the samples collected on other planets, something more comprehensive is needed, Adam says, like the new study’s framework.

And that’s just the beginning. “The value of this [catalog] is that it’s ongoing and potentially multigenerational,” Adam says. “We can go back to it again and again and again for different kinds of questions.”

“I think we have a lot more we can do,” agrees Shaunna Morrison, a mineralogist at the Carnegie Institution and coauthor of the new studies. “We’re just scratching the surface.”

Widespread volcanic eruptions around 202 million years ago had a profound effect on Earth’s climate, triggering a mass extinction event that killed off three-fourths of the planet’s species, including many large reptiles. Yet dinosaurs, somehow, survived and went on to thrive.

Dinosaurs are often thought of as heat-loving, well suited to the steamy greenhouse environment of the Triassic Period. But the secret to their survival may have been how well adapted they were to the cold, unlike other reptiles of the time. The dinosaurs’ warm coats of feathers could have helped the creatures weather relatively brief but intense bouts of volcanic winter associated with the massive eruptions, researchers report July 1 in Science Advances.
“We’ve known for a while that there were probably volcanic winters” associated with the massive eruptions, says paleontologist Paul Olsen of the Lamont-Doherty Earth Observatory at Columbia University. Along with carbon dioxide, volcanoes spew sulfur particles into the atmosphere that can darken skies for years and lower global temperatures — as the Philippines’ Mount Pinatubo did after its powerful 1991 eruption (SN: 8/8/18). “But how [such winters] fit into the picture of the end-Triassic mass extinction has been very unclear.”

In the new study, Olsen and his colleagues present the first physical evidence that not only did such winters occur at the end of the Triassic, but also that dinosaurs were there to weather them. At a site called the Junggar Basin, which at the close of the Triassic was found high in the Arctic Circle, the team identified rock fragments that could only have been deposited by ancient ice alongside the footprints of dinosaurs.

“There is a stereotype that dinosaurs always lived in lush tropical jungles,” says Stephen Brusatte, a paleontologist at the University of Edinburgh who was not involved in the new study. “But this new research shows convincingly that the higher latitudes would have been freezing and even covered in ice during parts of the year” at the beginning of the rise of the dinosaurs, he says.

The Triassic Period ended with a bang beginning around 202 million years ago, as the supercontinent Pangea began to break apart. Massive volcanic eruptions burst forth as the crust split, opening up a basin that became the Atlantic Ocean. The hardened lava from those eruptions now spans 7 million square kilometers across Africa, Europe and North and South America, forming a rock sequence collectively known as the Central Atlantic Magmatic Province, or CAMP.

Carbon dioxide levels were extremely high during the late Triassic and early Jurassic, much of it now thought to have been pumped into the atmosphere by those eruptions. Earth has been assumed to have been in a steamy greenhouse state as a result. Supporting this hypothesis is the fact that there’s no evidence of any polar ice sheets at the time; instead, thick forests extended all the way to the poles.

The Junggar Basin, in what’s now northwestern China, was one such region, covered with forests of conifers and deciduous trees growing alongside a massive ancient lake. Dinosaurs certainly lived there: No bones have yet been discovered at the site, but many footprints of the creatures are preserved in the shallow-water siltstones and sandstones that formed at the bottom of the lake.
The new data suggest that — despite the extremely high CO2 levels — this region also experienced harsh, frigid winters, with the lake at least partially freezing over. The evidence comes from the same rocks that bear the footprints. Analyzing the distribution of grain sizes in the rocks, the researchers determined that a large portion of the grains weren’t part of the original lake mud, but had been carried there from elsewhere.

The most likely explanation, Olsen says, is that these grains are “ice-rafted debris” — a well-known phenomenon in which bits of rock freeze to the base of ice along a shoreline, and then hitch a ride with the ice as it eventually drifts into open water. As the floating ice melts, the bits of rock sink, deposited in new territory.

Volcanic winters might last for tens or even hundreds of years, Olsen says, depending on how long volcanoes continue to erupt. In this case, the huge sheets of lava linked to the CAMP eruptions point to at least tens of thousands of years of eruption pulses, maybe even a million years. That could have kept the winters going for a good long time — long enough to drive many less-well-insulated reptiles off the face of the Earth, he adds. Episodes of those freezing conditions may have even extended all the way to the tropics, the team says.

Evidence of feathers has been found in the fossils of many types of dinosaurs, from carnivorous theropods to herbivorous ornithischians. Recent reports that flying reptiles called pterosaurs had feathers too now suggests that the insulating fuzz has been around for even longer than once thought — possibly appearing as early as 250 million years ago, in a common ancestor of dinosaurs and pterosaurs (SN: 4/29/22).

Thanks to those insulating feathers, dinosaurs were able to survive the lengthy winters that ensued during the end-Triassic mass extinction, Olsen and colleagues say. Dinosaurs might then have been able to spread rapidly during the Jurassic, occupying niches left vacant by less hardy reptiles.

This study “shows the complexity of disentangling not only the success of certain groups, but also the causes and effects of mass extinction events,” says paleontologist Randall Irmis of the University of Utah in Salt Lake City, who was not connected with the study. “There’s a pretty good consensus that [the CAMP eruptions are] the cause of the mass extinction — but there are a lot of subtleties we haven’t appreciated.”

That dinosaurs living in the far north at the time were able to survive due to their feathery insulation makes sense, Irmis says. But whether a volcanic winter caused by dimming could have extended far enough south to freeze the tropics too — giving dinosaurs a similar advantage there — isn’t yet clear. “Dimming is a global effect, but how that plays out is a lot more severe at the poles compared to low latitudes.”

Feathers are probably just one of many reasons why dinosaurs diversified and spread rapidly across the globe at the start of the Jurassic, Irmis says. “There’s a lot that plays into why they became such a successful group.”

Monkeypox is not yet a global public health emergency, the World Health Organization said June 25.

The decision comes as the outbreak of the disease related to smallpox continues to spread, affecting at least 4,100 people in 46 countries as of June 24. That includes at least 201 cases in the United States. Those cases have been found in 25 states and the District of Columbia, according to the U.S. Centers for Disease Control and Prevention.
“Controlling the further spread of outbreak requires intense response efforts,” and the situation should be reevaluated in a few weeks, the WHO committee evaluating the outbreak said in an announcement.

The declaration of a public health emergency would have potentially made it easier to get treatments and vaccines to people infected with or exposed to the virus. Some medications and vaccines that could help fend off monkeypox are approved for use against smallpox, and can be used against monkeypox only with special authorization.

The virus that causes monkeypox, named for its discovery in monkeys in 1958 though it is probably a virus that mainly infects rodents, is not a new threat. Countries in central Africa, where monkeypox is endemic, have had sporadic outbreaks since researchers found the first human case in 1970. Places in western Africa had few cases until 2017. But most cases outside the continent were travel-related, with limited spread to others (SN: 5/26/22).

“Monkeypox has been circulating in a number of African countries for decades and has been neglected in terms of research, attention and funding,” WHO director-general Tedros Ghebreyesus said in a statement announcing the decision. “This must change not just for monkeypox but for other neglected diseases in low-income countries as the world is reminded yet again that health is an interconnected proposition.”

Monkeypox typically kills fewer than 10 percent of people who contract it. At least one person has died in the global outbreak.

As case numbers climb, researchers are working to decipher the genetic blueprint of the virus, in hopes of uncovering whether some viral mutations might explain why the virus has quickly gained a foothold in new places.

Tracing the mutations
The closest known relative of the versions of the virus behind the global outbreak comes from Nigeria, hinting that the outbreak may have got its start there.

In the newest surge in cases, scientists have uncovered more viral changes than anticipated — a sign that the virus may have been circulating undetected among people for a while, perhaps since Nigeria’s 2017–2018 monkeypox outbreak, new research suggests. What’s more, a group of enzymes known for their virus-fighting abilities in the body may be to blame for many of those mutations.

A genetic analysis of monkeypox viruses involved in the global outbreak from 15 people across seven countries shows that these viruses have an average of 50 more genetic tweaks than versions circulating in 2018 and 2019, researchers report June 24 in Nature Medicine. That’s roughly six to 12 times as many mutations as scientists would have expected the virus to develop over that time. Unlike some other types of viruses, poxviruses, which include smallpox and monkeypox viruses, typically mutate fairly slowly.

The changes have a pattern that is a hallmark of an enzyme family called APOBEC3, the researchers say. These enzymes edit DNA’s building blocks — represented by the letters G, C, A and T — in a specific way: Gs change to As and Cs to Ts. The analysis found that particular pattern in the viral sequences, suggesting that APOBEC3s are responsible for the mutations.

Ideally, so many DNA building blocks are swapped for another that a virus is effectively destroyed and can’t infect more cells. But, sometimes, APOBEC3 enzymes don’t make enough changes to knock out the virus. Such mutated, though still functional, viruses can go on to infect additional cells, and possibly another person.

A big question, though, is whether the genetic tweaks seen in the monkeypox virus are helpful, harmful or have no effect at all on the virus.

While it’s still unknown whether the enzymes are directly responsible for the changes in the monkeypox virus, similar mutations are still popping up, the team found. So, APOBEC3s may still be helping the virus change as it continues to spread. One member of the enzyme family is found in skin cells, where people with monkeypox can develop infectious pox lesions.
Different symptoms
Symptoms reported in the global outbreak have been generally milder than those reported in previous outbreaks, perhaps allowing the disease to spread before a person knows they’re infected.

It is not clear whether those differences in symptoms are related to changes in the virus, Inger Damon, director of the CDC’s Division of High-Consequence Pathogens and Pathology, said June 21 in a news briefing hosted by SciLine, a service for journalists and scientists sponsored by the American Association for the Advancement of Science.

Typically, in previous outbreaks, people would develop flu-like symptoms, including fever, headaches, muscle aches and exhaustion about a week or two after exposure to the virus. Then, one to three days after those symptoms start, a rash including large pus-filled lesions pops up generally starting on the face and limbs, particularly the hands, and spreads over the body. Though generally milder, those symptoms are similar to smallpox, but people with monkeypox also tend to develop swollen lymph nodes.

All patients in the U.S. outbreak have gotten rashes, Damon said, “but the lesions have been scattered or localized to a specific body site, rather than diffuse, and have not generally involved the face or the … palms of the hand or the soles of the feet.” Instead, rashes may start in the genital or anal area where they can be mistaken for sexually transmitted diseases, such as syphilis or herpes, she said.

In many cases, the rashes have not spread to other parts of the body. And the classical early symptoms such as fever have been “mild and sometimes nonexistent before a rash appears,” Damon said.

Monkeypox is transmitted from person to person through close skin-to-skin contact or by contact with contaminated towels, clothes or bedding. It may also be spread by droplets of saliva exchanged during kissing or other intimate contact. The CDC is investigating whether the virus might be spread by semen as well as skin-to-skin contact during sex, Agam Rao, a captain in the U.S. Public Health Service, said June 23 at a meeting of the CDC’s Advisory Committee on Immunization Practices.

“We don’t have any reason to suspect it is spread any other way,” such as through the air, Rao said.

In Nigeria, more monkeypox cases have been recorded among women, while the global outbreak has affected mainly men, particularly men who have sex with men. Experts warn that anyone can be infected with monkeypox, and some people face an increased risk of severe disease. Those at increased risk include children, people who are immunocompromised, pregnant people and people with eczema.

The risk of catching monkeypox through casual contact is still low in the United States, Rao said. But data she presented show that while people in the country have contracted monkeypox while traveling abroad, cases have also spread locally.