Hello Nature readers, would you like to get this Briefing in your inbox free every day? Sign up here.

A delicate, smoky blue jellyfish-like creature floats in dark water.

Comb jellies, or ctenophores, are the closest living relative to the first animal. (Jacques Julien/Alamy Stock Photo)

The ancestor of all animals

Ctenophores, also called comb jellies, are the sister group of all living animals, scientists have discovered. The team compared the comb jelly Bolinopsis microptera to sponges — another contender for the most ancient creature on Earth — along with three unicellular relatives of animals. The pattern of genes on the jellies’ chromosomes revealed that they evolved first. That means that early animals were surprisingly complex: they had a well-developed nervous system, and could probably swim around freely. “We have to rethink the function and the structure of the early ancestor of animals. It wasn’t like a simple sponge,” says evolutionary biologist Paulyn Cartwright.

Scientific American | 6 min read

Reference: Nature paper

US debt-ceiling crisis could cost science

The US government could run out of money as early as next week if lawmakers fail to reach an agreement to service the country’s debt. Republican lawmakers have proposed slashing the government’s spending in exchange for raising the ‘debt ceiling’ — a congressionally-imposed limit on how much the government can borrow to pay for its expenses. If the stalemate lasts, the United States will default on its debt payments for the first time, with unpredictable consequences. The country could be thrown into financial turmoil, and federal agencies such as the National Institutes of Health could be forced to stop paying scientists’ grants and salaries. If Republicans succeed in their quest, science-agency budgets will be on the block; if a deal is struck, next year’s funding could remain flat at this year’s levels, in one of the more positive scenarios.

Nature | 5 min read

First sight of the signals of chronic pain

Researchers have used a device implanted in the brain to record, for the first time, objective signs of chronic pain. Several times a day for up to six months, the implant recorded four people’s brain activity, which scientists matched to their self-reported symptoms. One participant had phantom pain from an amputated leg; the rest had unexplained sensations after a stroke. When participants felt chronic pain, brain activity in the orbitofrontal cortex was detected. A different region of the brain was active when they experienced pain from touching a hot object. “Chronic pain is actually its own separate disease that is not simply an extension of pain in general,” says physician-scientist and study co-author Prasad Shirvalkar.

The Wall Street Journal | 5 min read

Reference: Nature paper

How a single gene turns scales into feathers

Manipulating a single gene pathway turns chickens’ scaly feet into feathery ones. The gene encodes the sonic hedgehog protein, a signalling molecule that is involved in embryonic development. “Our results indicate that an evolutionary leap — from scales to feathers — does not require large changes in genome composition or expression,” says evolutionary biologist Michel Milinkovitch.

Cosmos | 3 min read

Reference: Science Advances paper

Features & opinion

Academia–industry hybrids open job doors

PhD projects and degree programmes in which students collaborate with companies, and those with built-in industry internships, give early-career scientists an edge on the job market. Earning a PhD has long been viewed as a launch pad into academia: students are trained to run experiments, secure grants and write papers. But this “monk-like existence does not prepare you for the careers that PhD graduates are actually having”, says provost David Madigan. Some countries, such as Australia, are investing heavily in industry-based PhD and postdoc programmes as part of a push to bridge the ‘valley of death’, where promising basic research often fails to get picked up and commercialized by private companies.

Nature | 11 min read

The dream of self-cloning crops

In 2019, the first self-cloning rice plants brought a palpable “sense of excitement” to plant science, says molecular biologist Mary Gehring. More than 400 plant species, including common ones such as dandelions, naturally reproduce through cloning — a process that scientists are now starting to copy over to staple crops. Self-cloning hybrid crops could preserve their unique genetics, a long-sought goal for plant breeders. Hybrid crops, made by crossing strains of inbred parents, are remarkably (and mysteriously) robust and high-yielding. But producing hybrid crops is labour-intensive, and the process must be repeated for each batch of seeds. Otherwise, genetic reshuffling during normal sexual reproduction means that the offspring will lose their parents’ favourable traits.

Science | 12 min read

Where I work

Libin Zhang bends down slightly to view sea cucumbers in a tank

Libin Zhang is executive deputy director of the Engineering Laboratory for Marine Ranching in the Institute of Oceanology of the Chinese Academy of Sciences.Credit: Yue Wu for Nature

Libin Zhang is using sea cucumbers such as Apostichopus japonicus to rebalance marine ecosystems. As the executive deputy director of the Engineering Laboratory for Marine Ranching in Qingdao, China, he studies how these creatures can be sustainably farmed while they help to clean degraded habitats. A. japonicus is usually green, but this tank contains some white and purple individuals. “The purple one is beautiful and contains beneficial compounds similar to those found in red wine, including astaxanthin, which has potent antioxidant and anti-inflammatory properties,” Zhang says. (Nature | 3 min read)

Quote of the day

“For all of the good scientists do in Antarctica, the impact we have is vast.”

Ecologist Pedro Echeveste reflects on how humans have left a mark on Earth’s most pristine continent: from discarded washing machines and abandoned table-football sets to toxic substances and microplastics. (The Guardian | 7 min read, including some remarkable and alarming images)