Laotian cave rewrites migration story
Two human bone fragments — from a skull and a leg — have been unearthed in the Tam Pà Ling cave in Laos. The fossils are older than previous finds from the cave and suggest that early modern humans were in the area up to 86,000 years ago. That’s earlier than previously thought, and calls into question hypotheses that Homo sapiens dispersed out of Africa and through Asia in a single rapid event that happened after the ending of a geological period 80,000 years ago. “I can’t overestimate the importance of having another point on our map for early modern humans in southeast Asia,” says anthropologist Miriam Stark. “Understanding southeast Asia is critical to understanding the world’s deep history,” she says.
Magnetism could explain homochirality
Magnetic minerals that were common on ancient Earth might be why nature shows a preference for the ‘left handed’ or ‘right handed’ versions of certain molecules that are essential for life. Some molecules have two mirror-image ‘chiral’ forms, and biology chooses just one: DNA, RNA and their building blocks are all right-handed; amino acids and proteins are all left-handed. Researchers found that magnetic minerals could have created an early surfeit of one-handed versions by causing more of one type to settle on their surfaces, kicking off the biological bias towards a single chiral form. “It’s a real breakthrough,” says origin-of-life chemist Jack Szostak. “Homochirality is essential to get biology started, and this is a possible — and I would say very likely — solution.”
Science | 6 min read
Reference: Science Advances paper
Moths are great pollinators, too
Moths are the unsung heroes of pollination in cities, accounting for one-third of pollinator visits in a study of moths and bees in Leeds, UK. “The whole reason why they’re overlooked is because bees, you see them in the day, but moths are obviously out at night,” says pollinator ecologist Emilie Ellis. Her team collected bees and moths in the city and examined the DNA of the pollen that they carried. Not only did the moths have a bigger role than expected, but the insects’ preferences differed: bees visited more wildflowers, whereas moths chose woody plants, such as trees and shrubs.
Features & opinion
Lab mice go wild
Neuroscientists are creating more naturalistic experiments to achieve a more nuanced understanding of animal — and human — behaviour. Some of the laboratory experiments that have been used for decades — such as training a mouse to push a lever to get a reward — require teaching an animal to complete specific, idiosyncratic tasks. The end result is like studying a “professional athlete”, says neuroscientist Tiago Branco. Armed with the latest technologies for brain imaging and movement tracking, researchers can now look at the natural and spontaneous behaviour of mice to glean holistic lessons that are more relevant to everyday activity.