From rocks to icebergs, the natural world tends to break into cubes
Perhaps the Cubists were right. Researchers have found that when everything from icebergs to rocks breaks apart, their pieces tend to resemble cubes. The finding suggests a universal rule of fragmentation at scales ranging from the microscopic to the planetary.
Ancient microbial arms race sharpened our immune system—but also left us vulnerable
At a recent symposium on the evolution of infectious diseases, University of California, San Diego (UCSD), pathologist Nissi Varki noted that humans suffer from a long list of deadly diseases—including typhoid fever, cholera, mumps, whooping cough, measles, smallpox, polio, and gonorrhea—that don’t afflict apes and most other mammals. All of those pathogens follow the same well-trodden pathway to break into our cells: They manipulate sugar molecules called sialic acids. Hundreds of millions of these sugars stud the outer surface of every cell in the human body—and the sialic acids in humans are different from those in apes.
After 40 years, researchers finally see Earth’s climate destiny more clearly
It seems like such a simple question: How hot is Earth going to get? Yet for 40 years, climate scientists have repeated the same unsatisfying answer: If humans double atmospheric carbon dioxide (CO2) from preindustrial levels, the planet will eventually warm between 1.5°C and 4.5°C—a temperature range that encompasses everything from a merely troubling rise to a catastrophic one.
Global warming shrinks bird breeding windows, potentially threatening species
For breeding birds, timing is everything. Most species have just a narrow window to get the food they need to feed their brood—after spring’s bounty has sprung, but before other bird species swoop in to compete. Now, a new study suggests that as the climate warms, birds are not only breeding earlier, but their breeding windows are also shrinking—some by as many as 4 to 5 days. This could lead to increased competition for food that might threaten many bird populations.
New genes control plant height, could lead to flood-proof crops
Stature matters to plants. Short crops can carry more grain without bending under their own weight—a key trait that helped power the Green Revolution in the 1960s. But tall plants are better at surviving long floods. Now, researchers have found two genes that together help control the height of rice plants: one that accelerates the elongation of the stem and another that acts as a brake. If the system is similar in other plants, scientists say it could be useful in the breeding of many kinds of crops.
The pandemic virus is slowly mutating. But is it getting more dangerous?
It’s only a tiny change. At some point early in the pandemic, one of the 30,000 letters in the genome of SARS-CoV-2 changed from an A to a G. Today, that mutation, at position 23,403, has spread around the world. It is found in the vast majority of newly sequenced viruses and has become the center of a burning scientific question: Has the mutation become so common because it helps the virus spread faster? Or is it just coincidence?
New method to edit cell’s ‘powerhouse’ DNA could help study variety of genetic diseases
In a biological beating of swords into plowshares, researchers have converted a bacterial toxin into a genome editing tool that, for the first time, can make precise changes to DNA in mitochondria, the cell’s power plants. The tool, which worked in lab experiments with human cells, could open the door to new studies of—and one day therapies for—dozens of hard-to-treat diseases caused by mutations in mitochondrial DNA (mtDNA). These rare conditions, which include Leber hereditary optic neuropathy and lethal infantile cardiomyopathy, collectively affect about one in 4000 people. Until now, research on these illnesses has been stymied in part because there was no way of reproducing the mutations in strains of mice.
Underwater caves in Mexico preserve one of the world’s oldest ochre mines
Crouching as she wound her way through a pinched underground corridor, a young woman grasped a torch in one hand, soot blackening the craggy ceiling above her. Guided by stacks of stones deeper and deeper in the darkness of the cave, she finally spied her prize: a blood-red vein of rock in the fire-lit wall. It would be 10,000 years before another pair of eyes saw it again.
Ancient DNA reveals a Bronze Age bias for male horses
Myths about horses and gender abound. Many equestrians, for example, say they prefer “predictable” geldings over “moody” mares, despite no real difference in their behavior while ridden. Now, a new study suggests our biased views of horses may have ancient origins. Based on ancient DNA from hundreds of horse skeletons, researchers suggest Bronze Age Eurasians overwhelmingly preferred male horses—preferences that may shed light on the earliest days of horse husbandry.
Pools in the Mexican desert are a window into Earth’s early life
The landscape—more than 300 turquoise-blue pozas scattered across 800 square kilometers, among marshes and majestic mountains—wasn’t the only draw. The waters, whose chemistry resembled that of Earth’s ancient seas, teemed with microbes; unusual bacterial mats and formations called stromatolites carpeted the shallows.