In science news around the world, authorities in the United Kingdom give the go-ahead for mitochondrial replacement therapy, U.S. President Barack Obama's administration finalizes a controversial rule designed to protect small streams and forests from coal mining, and Mount Yasur on the Pacific archipelago of Vanuatu becomes the first volcano to burp up a plume of carbon dioxide measured from space. Also, researchers discover that the glowworms illuminating New Zealand's caves use a surprising ingredient to trap their prey. And an MRI study reveals that pregnancy strikingly alters the architecture of women's brains during their first pregnancy in ways that last for at least 2 years.