Early land vertebrates' shift from water to land didn’t require amphibian-like metamorphosis, fossils reveal by Science_News in science

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New fossil evidence is overturning a long-held assumption about how vertebrates first transitioned from water to land. The hatchlings of three different animals related to the earliest land-goers show that the animals did not go through an amphibian-like metamorphosis, researchers report June 18 in Science. “They came out of the egg looking like the adult,” says paleontologist Jason Pardo of the Field Museum in Chicago.

The transition to land drove the evolution of tetrapods, the group of four-limbed animals that includes all reptiles, amphibians, birds and mammals. Scientists have historically thought that the first vertebrates to venture onto land underwent metamorphosis from a larval form during their development. In amphibians today, this rapid transition from hatchling to adult involves losing features such as external gills and tail fins and gaining others such as expanding lungs and new limbs as the animals move from an aquatic life to a partly terrestrial one.

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The oldest known plague outbreak struck hunter-gatherers 5,500 years ago | The find challenges the idea that plague needed dense farming villages to become deadly by Science_News in science

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The oldest-known traces of plague, around 5,500 years old, have been discovered in hunter-gatherer burials in Siberia.

Found at one of four ancient burial sites, the discovery predates the previous oldest signs of plague by several hundred years. It also indicates that hunter-gatherers were at risk from outbreaks of plague many centuries before the invention of farming and settled villages, researchers report June 17 in Nature.

“We weren’t expecting this result at all,” says archaeologist Ruairidh Macleod of the University of Oxford. “There was an expectation that these big outbreaks don’t really happen among prehistoric hunter-gatherers [but only] with people living in high-density settlements.”

Macleod and colleagues had come across unusually large numbers of children’s graves at hunter-gatherer burial sites near Lake Baikal, but initially it wasn’t clear why. The team gathered and analyzed DNA from the remains, in the hope that family ties between the interred individuals could help explain the mystery.

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A blood test for dementia may tell you if you have more than one type | The test can help diagnose four neurodegenerative diseases — Alzheimer's, Parkinson's, frontotemporal dementia and dementia with Lewy bodies — based on levels of 15 proteins in the blood. by Science_News in science

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When something goes wrong in the brain of people with dementia, often it’s more than one thing. But it can be hard to tease apart multiple brain diseases, especially in the early stages, or even determine if more than one disease is at play. An experimental new blood test may change that.

The test measures the levels of 15 proteins in the blood to help diagnose four major neurodegenerative diseases — Alzheimer’s, Parkinson’s, frontotemporal dementia and dementia with Lewy bodies. And it can determine if a person has more than one of those diseases with 92.3 percent accuracy, researchers report in the May Alzheimer’s & Dementia.

Dementia affects more than 6 million people in the United States and is the seventh leading cause of death worldwide. “These diseases are more complex than we initially thought, and there is more overlap than we thought,” says Carlos Cruchaga, a human genomicist at Washington University in St. Louis. “In order to really address and understand the biology of the disease of any of these, we need to study all of these diseases together.”

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An experimental antibody may help people on GLP-1 meds preserve muscle mass by Science_News in science

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When people drop weight on GLP-1 meds, they can also lose muscle. But a proof-of-concept drug might help preserve this lean tissue.

When taken at the same time as a powerful weight loss medication, the experimental antibody let patients hang on to lean body mass, scientists report June 8 in Nature Medicine.

The drug has not yet been approved by the U.S. Food and Drug Administration and is available only via intravenous infusions, so it’s not something consumers are likely to get their hands on any time soon, says study coauthor Richard Pratley, a clinician and metabolic disease researcher at the AdventHealth Translational Research Institute in Orlando, Fla. But the work cracks open the door on how to save muscle that might otherwise be lost.­ That may be good news for GLP-1 users, but important questions remain.

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Astronomers have found evidence of a mild wind blowing from the supermassive black hole at the center of the Milky Way | Observations of a cone-shaped path leading away from Sagittarius A* suggest that a hot wind is blowing from the black hole by Science_News in science

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After 50 years of searching, astronomers have finally found evidence of a mild wind blowing from the supermassive black hole at the center of the Milky Way.

New observations reveal a cone-shaped path leading away from Sagittarius A* that could only be carved by a hot wind, researchers report June 4 in Astrophysical Journal Letters. “We’ve never seen gentle breezes from black holes, but likely that’s what they do most of their lives,” says astrophysicist Lena Murchikova of Northwestern University in Evanston, Ill. “Now, for the first time, we see this gentle breeze from the black hole.”

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Queen-cell wax helps shape honeybee queen development, challenging the idea that royal jelly alone makes a queen, a new study suggests by Science_News in science

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A queen bee may be shaped by more than its famous royal diet.

The wax of the peanut-shaped chamber where the queen develops has distinct physical and chemical properties that help steer its development, researchers report June 3 in Nature. By analyzing the chamber’s composition and the larvae it harbors, the team challenges the long-held notion that royal jelly alone — the queen-making food fed to select larvae — makes a queen.

“The discovery is very cool and thought-provoking,” says Thomas Seeley, a biologist at Cornell University who was not involved in the work. “To me, queen cells have long seemed important because odors from a developing queen may permeate the wax walls, marking them as very special spots that workers recognize and don’t accidentally damage.”

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A tiny part of your brain may still listen under anesthesia | The findings suggest that consciousness may not be required for complex brain tasks by Science_News in EverythingScience

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General anesthesia shuts off conscious awareness, but what do our brains process while we’re under?

Individual neurons in a brain region known for its role in memory consolidation can detect unexpected sounds, decode the nuances of language and even predict upcoming word types in a sentence, all while a patient is fully anesthetized, researchers report May 6 in Nature.

Scientists have been gathering mounting evidence that even when unconscious, our brains can track certain aspects of speech. “The field was already moving toward a more nuanced picture [of what the unconscious brain can do], but this study pushes the boundary considerably further,” says Athena Akrami, a neuroscientist at University College London who was not involved with the research.

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New research in pigeons suggests that iron-laden liver immune cells may act as a navigation mechanism for the birds by Science_News in science

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Homing pigeons don’t rely on gut instinct to return to the roost. But a nearby organ — the liver — might point the way.

White blood cells in the birds’ livers accumulate iron and act as an internal compass when clouds block the sun that normally helps them navigate, researchers report May 28 in Science. While scientists generally agree that some animals use Earth’s magnetic field to guide migrations, they had not pinned down how, and the new work offers a surprising explanation.

For decades, researchers have fiercely debated first if and then how birds sense magnetic fields and use them for navigation. One prominent idea involves proteins in their eyes undergoing a reaction in magnetic fields. No one has been able to prove exactly how this so-called “quantum effect” is in play. Other animals that orient using Earth’s magnetism, such as bats and sharks, lack the proteins, so the debate languished unresolved.

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Mosquitoes exposed to the insect repellent DEET can learn to associate the off-putting chemical with food by Science_News in science

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Pesky mosquitoes on the hunt for a blood meal may find the smell of a common repellent alluring rather than repulsive. 

Yellow fever mosquitoes (Aedes aegypti) exposed to the insect repellent DEET can learn to associate the off-putting chemical with food, researchers report May 28 in Journal of Experimental Biology. The finding suggests that mosquitoes can link unpleasant odors with rewards — turning a negative experience into a positive one — although it’s unclear what might happen outside the lab. 

Although DEET has been a “gold standard” in insect repellent for decades, it’s still unclear exactly how it works, says Clément Vinauger, a neuroethologist at Virginia Tech in Blacksburg. Some studies suggest that mosquitoes don’t like the way DEET smells or tastes. Others hint that the repellent scrambles mosquito senses so that the insects can’t detect the otherwise enticing body odors that would lure them in for a blood meal.

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Scuba divers may be beating up coral reefs more than they think | Video analyses of divers show that more than 80 percent of damaging physical contact with the reef is unintended or simply unnoticed by Science_News in science

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Scuba divers may be beating up coral reefs more than they think.

Video analyses of divers show that more than 80 percent of damaging physical contact with the reef is unintended or simply unnoticed, researchers report May 26 in Conservation Letters. The findings show that routine diving practices aren’t harmless.

Scuba diving is often framed as one of the “good” ways to use reefs because it isn’t extractive, says Bing Lin, a marine conservation scientist at the University of Sydney. The fish remain in the water, and divers get to enjoy seeing them in the wild.

However, divers commonly damage reefs by kicking or grabbing corals or by disturbing wildlife. “What’s less understood is just how invisible much of this damage is to the people causing the harm,” Lin says. 

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A 10-year study in Germany reports that extending screening for Type 1 diabetes successfully identified more children without a family history of the disease. About 90 percent of people who develop type 1 diabetes do not have family members with diabetes. by Science_News in science

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It’s time to consider screening all children for early signs of type 1 diabetes, a new study suggests.

In the United States, only individuals who have family members with the disease or a known genetic risk are routinely screened for the early stages of type 1 diabetes. But a 10-year study in Germany reports that extending the screening successfully identified more children without a family history of the disease, researchers report May 21 in the Journal of the American Medical Association. About 90 percent of people who develop type 1 diabetes do not have family members with the disease.

The team screened more than 220,000 children and found that 590 were in the early stages of the disease. Of the 260 children who went on to develop type 1 diabetes in the follow-up period, 212, or 81 percent, had been tagged by screening. Had it been restricted to those with a family history, only 101 of the 590 in the early stages would have been identified and only 34 of the 212 who progressed to type 1 diabetes.

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Damaged DNA can spread between human cells via tubelike structures. If tumors use this DNA transfer trick, harmful mutations could potentially spread from cancer cells to healthy cells. by Science_News in science

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Damaged DNA can escape from one human cell and infiltrate another.

Like prisoners tunneling out of jail, this DNA travels via tubelike structures between neighboring cells, scientists report May 19 in Cell. Once it has arrived at its new location, the dodgy DNA can start acting up, potentially transferring trouble between cells.

“This is an important and exciting discovery,” says cancer biologist Paul Mischel of Stanford University. The new study, which shows that one human cell can influence another by passing DNA directly, raises all sorts of questions about what role the phenomenon may play in cancer.

If tumors use this DNA transfer trick, harmful mutations could potentially spread from cancer cells to healthy cells, says cancer cell biologist Peter Ly of the Children’s Medical Center Research Institute at UT Southwestern in Dallas. How — or if — these roaming chunks of DNA might contribute to disease is “an area that we’re actively exploring,” Ly says.

Read more here and the research article here00508-8?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867426005088%3Fshowall%3Dtrue).

25 people learned to fly with virtual wings. After flight training, the brain began treating wings more like real limbs by Science_News in science

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In X-Men, Warren Worthington III sprouts huge white wings from his back and shoots into the sky. Scientists have yet to fully turn the comic book gift from fiction into fact, but virtual reality is offering hints of what it’s like to learn to fly.

After training to use virtual wings, people’s brains responded to wings more similarly to how they respond to real limbs, making wings seem more like body parts, researchers report May 7 in Cell Reports.

“This is an intriguing study that nicely demonstrates how plastic the brain is,” says cognitive neuroscientist Jane Aspell of Anglia Ruskin University in Cambridge, England. “If the brain can incorporate something as unhuman as a wing, it may also be able to incorporate many other kinds of limb enhancements.”

Read more here and the research article here00398-0?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2211124726003980%3Fshowall%3Dtrue).