Neanderthal–human baby-making was recent — and brief

Mixing between Neanderthals and Homo sapiens lasted less than 7,000 years — a remarkably short time considering that almost every living individual not of African ancestry carries a substantial amount of Neanderthal DNA. Researchers compared the genomes of individuals who lived between 2,200 and 45,000 years ago with those of modern people and found that the genetic intermingling started around 47,000 years ago. It ended around the time when Neanderthals went extinct.

Counting crows

Carrion crows (Corvus corone) can reliably caw a number of times from one to four on command — a skill that had only been seen in people. Over several months, birds were trained with treats to associate a screen showing the digits, or a related sound, with the right number of calls. The crows were not displaying a ‘true’ counting ability, which requires a symbolic understanding of numbers, say researchers. But they are nevertheless able to produce a deliberate number of vocalisations on cue.

Bizarre bacteria scramble workflow of life

Bacteria have stunned biologists by reversing the usual flow of information. Typically genes written in DNA serve as the template for making RNA molecules, which are then translated into proteins. Some viruses are known to have an enzyme that reverses this flow by scribing RNA into DNA. Now scientists have found bacteria with a similar enzyme that can even make completely new genes — by reading RNA as a template. These genes create protective proteins when a bacterium is infected by a virus.

Elusive element coaxed into compound

Promethium, a rare and mysterious radioactive element from the far reaches of the periodic table, has been made into a ‘complex’ for the first time. In this type of compound, promethium is bound to a few surrounding molecules. The feat fills a long-standing gap in our knowledge of chemistry and could lead to better methods for separating promethium from similar elements in nuclear waste, for example.

A Chinese-language ChatGPT

The Chinese-made chatbot ChatGLM performs as well as ChatGPT on many measures and even outperforms it in Chinese, say its creators. Models that are tailored to different languages avoid “oversimplifying or neglecting the specific characteristics of certain languages and cultures”, says machine-learning specialist Adina Yakefu. Although ChatGPT and many of its rivals can respond in a variety of languages, most of them are built by US companies and mainly use English. By contrast, ChatGLM is designed to work in both Chinese and English.

Lab-grown sperm and eggs: ‘epigenetic’ reset in human cells paves the way

Researchers have discovered a protein that promotes an ‘epigenetic’ reset in human cells — a small but crucial step in their development into sperm or eggs. The epigenome affects whether genes are turned on or off, and helps to differentiate, for example, a brain cell from a liver cell. The cells in the study stopped developing further after epigenetic reprogramming, so before we can grow eggs and sperm in a dish.

First ‘bilingual’ brain-reading device decodes Spanish and English words

An AI-powered brain implant has helped, for the first time, a paralysed bilingual person speak in both their languages. An artificial intelligence (AI) system decodes the man’s neural patterns and interprets the language he’s using — English or his native Spanish — based partly on which combination of words makes the most sense.

Found at last: long-lost branch of the Nile

The remains of an ancient branch of the Nile River has been found near the Giza pyramid complex in Egypt — hinting at why so many were built there. The pyramids there are now many kilometres away from the Nile. Satellite images and geological data now confirm that a tributary of the river — which researchers have named the Ahramat Branch — used to run nearby several thousand years ago. The waterway would have provided a convenient way to transport materials to the sites.

‘Quantum internet’ demonstration in cities is most advanced yet

Three research teams were each able to create quantum-entangled states over several kilometres of existing optical fibres in real urban areas. Entanglement is when two or more objects are linked so that they contain the same information even when they are far apart.

Human embryos embrace asymmetry to form the body

The two cells that make up a one-day old embryo make dramatically different contributions to a human body. This is contrary to the idea that embryonic cells don’t specialise until later in development. Studies with mice, and now with human embryos, have shown that one of the first two cells develops to become most of the mammalian body, whereas the other mainly forms the yolk sac. The cell that divides faster seems to form the body, but it’s not clear why this preference develops. The finding could eventually improve screening for in vitro fertilisation to select embryos more likely to develop into a fœtus and lead to successful pregnancies.

How does ChatGPT ‘think’?

Researchers are borrowing approaches from psychology and neuroscience to crack open the ‘black box’ of artificial intelligence (AI) systems.

Brain-reading device is best yet at decoding ‘internal speech’

A brain-computer interface device is the first to decode words entirely from neuronal recordings, without the aid of spoken or mimed speech. The system used arrays of tiny electrodes implanted in the brains of two people with spinal-cord injuries. It decoded one participant’s imagined speech with 79% accuracy and the other’s with 23% accuracy. Some neurons were active only during internal speech and not when the person spoke aloud, suggesting the brain processes imagined speech differently. Clinical applications are still a long way off.

Cubic millimetre of brain mapped in spectacular detail

Researchers have created an exquisitely detailed atlas of a tiny piece of one woman’s brain, which had been removed during surgery to treat her epilepsy. The sample was cut into thousands of nanometre-thick slices and each was imaged with electron microscopes. AI tools then classified different structures and cells, and created a 3D reconstruction of the sample.

Breakthrough paves way for ultra-precise ‘nuclear’ timekeepers

Researchers have used a laser to prompt tiny energy shifts in an atomic nucleus — a major step towards building nuclear clocks. These could be around 10 times more accurate than the world’s current best timekeepers, known as optical clocks, and less sensitive to disturbances. To turn the system into an actual clock, physicists will need to build higher-resolution lasers that nudge the nucleus with more precision.

Optical Clock

Discovery of atmosphere on an Earth-like exoplanet

Investigations using the James Webb Space Telescope have confirmed that the exoplanet 55 Cancri e has a carbon-based atmosphere — the first time an atmosphere has been detected surrounding a rocky planet similar to Earth outside the Solar System. The planet orbits very close to its Sun-like star and can’t support life as we know it, in part because it is probably covered by a magma ocean.

New Kind of Dinosaur Egg Discovered

Palæontologists have discovered dinosaur eggs in eastern China that were softer and less brittle than hard-shelled eggs — but not quite soft-shelled either. The eggs, which date back to some 66-145 million years ago, suggest that dinosaurs were more diverse than previously assumed.

What if dark energy is weakening?

A pioneering cosmic-mapping project seems to show that dark energy could be getting weaker, with potential implications for theories of how the Universe has evolved and for what its future might hold. The mysterious force is like reverse gravity, pushing everything apart and causing the Universe to expand faster and faster, getting colder and emptier. Initial results from the Dark Energy Spectroscopic Instrument in Arizona hint that dark energy is not a constant after all, which means the Universe’s expansion could start to slow down. But researchers say that the evidence for changes in dark energy is still very uncertain.