No more, no less: six to eight hours sleep each day slows biological ageing

Hello Nature readers,
Today we learn that between six and eight hours of sleep each day seems to be a ‘sweet spot’, uncover unexpected interbreeding between Denisovans and Homo erectus, and consider how the appearance of antibiotics could be driving antimicrobial resistance.

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Seven hours is sleep ‘sweet spot’

Getting about six to eight hours of sleep each day is linked to a lower risk of death and disease — any more or less is associated with accelerated biological ageing. Researchers analysed health data from more than 500,000 people and found that the ticks of 12 biological ‘clocks’ were generally slowest in people who got about seven hours of sleep, though the optimum amount of sleep time varied slightly between clocks that indicate age in different organs, and between men and women.

Mum’s a Denisovan, Dad’s a Homo erectus

Ancient proteins extracted from the teeth of Homo erectus individuals that lived in China suggest that the group might have interbred with Denisovans, another archaic human species. Researchers used enamel proteins from six H. erectus individuals and identified an amino-acid variant that’s previously been seen in Denisovans. The group also identified two amino-acid sequence variants shared by all six individuals that set H. erectus apart from humans and other human relatives — something that has proved hard to find in the past.

Antiviral pill prevents COVID infection

For the first time, an antiviral pill has been shown to prevent people coming down with COVID-19 after being exposed to the SARS-CoV-2 virus. The drug, ensitrelvir, blocks an enzyme that coronaviruses need to make new copies of themselves. The results come years after the peak of the COVID-19 pandemic, but the drug could be a lifeline for those who still face real danger from the virus, such as care-home residents or transplant recipients on immune-suppressing medication.

India’s DNA map reveals amazing diversity

India’s biggest gene-sequencing effort has shed new light on the diversity of the population, identifying nearly 130 million genetic variants, almost a third of which have not been reported previously. The GenomeIndia project analysed the whole genomes of almost 10,000 people, uncovering 44 million variants that weren’t already in global scientific databases. The study also revealed genetic risk factors in some populations, such as variants in genes that affect how the body processes certain drugs, variants linked to anaesthesia-related complications and extremely high levels of genetic homozygosity — when individuals inherit identical forms of a gene at a particular chromosome location from both parents. This can be a risk factor for recessive genetic diseases.

The last taxidermist

Tim Bovard is the last full-time taxidermist at any museum in the United States. He maintains the animal mounts at the Museum of Natural History in Los Angeles, some of which have been in the museum’s collection for more than a century. A life-long animal enthusiast, Bovard is still dedicated to his craft after more than four decades at the museum, often sleeping in his office to cut out his commute. “It wouldn’t be for everybody,” Bovard says. “But I am known to be slightly different. That’s putting it sort of mildly.”

Antibiotics look too similar to other drugs

The physical appearance of antibiotic drugs is contributing to the rise of antimicrobial resistance, argues medical microbiologist Heiman Wertheim. If people can’t easily distinguish antibiotics from other medications, they won’t use them with care. And it isn’t just a problem among people prescribed the drugs: “I’ve asked audiences of infectious-disease specialists, who you’d assume would know, to identify an antibiotic in a photograph of three capsules,” he says. “Most of them pick the green and yellow one, which is actually a painkiller.”