Archivo: Science

Unlike most cells in our bodies, the neurons in our brain can scramble their genes, scientists have discovered. This genome tampering may expand the brain’s protein repertoire, but it may also promote Alzheimer’s disease, their study suggests.

During the Cambrian, which began about 540 million years ago, nearly all modern animal groups—as diverse as mollusks and chordates—leapt into the fossil record. Those early marine animals exhibited a dazzling array of body plans, as though evolution needed to indulge a creative streak before buckling down. For more than a century, scientists have struggled to make heads or tails—sometimes literally—of those specimens, figure out how they relate to life today, and understand what fueled the evolutionary explosion.

Ask medieval historian Michael McCormick what year was the worst to be alive, and he’s got an answer: “536.” Not 1349, when the Black Death wiped out half of Europe. Not 1918, when the flu killed 50 million to 100 million people, mostly young adults. But 536. In Europe, “It was the beginning of one of the worst periods to be alive, if not the worst year,” says McCormick, a historian and archaeologist who chairs the Harvard University Initiative for the Science of the Human Past.

We know the menagerie of microbes in the gut has powerful effects on our health. Could some of these same bacteria be making a home in our brains? A poster presented here this week at the annual meeting of the Society for Neuroscience drew attention with high-resolution microscope images of bacteria apparently penetrating and inhabiting the cells of healthy human brains. The work is preliminary, and its authors are careful to note that their tissue samples, collected from cadavers, could have been contaminated. But to many passersby in the exhibit hall, the possibility that bacteria could directly influence processes in the brain—including, perhaps, the course of neurological disease—was exhilarating.

Daubed in orange ochre at least 40,000 years ago, images of what appear to be wild cattle on the Indonesian island of Borneo are now the oldest known figurative paintings in the world. Painted in a remote limestone cavern, they are more than 4000 years older than the previous record holders on nearby Sulawesi, and they add to evidence that thriving artistic traditions were emerging simultaneously in Europe and Asia.

Early humans faced countless challenges as they fanned out of Africa: icy conditions, saber-tooth cats, and, according to a new study of ancient skeletons, an unusually high number of birth defects, both debilitating and relatively inconsequential. It’s unclear why such abnormalities seem to be so common, but scientists say one strong possibility is rampant inbreeding among small hunter-gatherer groups.

The shape of a mother’s birth canal is a tug-of-war between two opposing evolutionary forces: It needs to be wide enough to allow our big-brained babies to pass through, yet narrow enough to allow women to walk efficiently. At least that’s been the common thinking. But a new study reveals birth canals come in a variety of shapes in women around the world.

Humans are awful at estimating a person’s age based on their face alone. This can lead not only to uncomfortable social situations, but also to critical errors in criminal investigations and enforcing age-based restrictions on such things as alcohol and gambling. New research shows people are usually off by about 8 years, and their estimate might be shaped by the last face they saw.

It sounds like science fiction: A research program funded by the U.S. government plans to create virus-carrying insects that, released in vast numbers, could help crops fight threats such as pests, drought, or pollution. “Insect Allies,” as the $45 million, 4-year program is called, was launched in 2016 with little fanfare. But in a policy forum in this week’s issue of Science, five European researchers paint a far bleaker scenario. If successful, the technique could be used by malicious actors to help spread diseases to almost any crop species and devastate harvests, they say. The research may be a breach of the Biological Weapons Convention (BWC), the piece argues.

In a small basement laboratory, Harry Levine, a Harvard University graduate student in physics, can assemble a rudimentary computer in a fraction of a second. There isn’t a processor chip in sight; his computer is powered by 51 rubidium atoms that reside in a glass cell the size of a matchbox. To create his computer, he lines up the atoms in single file, using a laser split into 51 beams. More lasers—six beams per atom—slow the atoms until they are nearly motionless. Then, with yet another set of lasers, he coaxes the atoms to interact with each other, and, in principle, perform calculations.