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Thirty years ago this week, a sheep named Dolly was born, the first mammal cloned from an adult cell. “It was absolutely crazy,” recalls biotechnology researcher Bruce Whitelaw. “We weren’t prepared for that.” Reproductive cloning is now being used to create polled cattle, pigs with organs more suitable for transplants, and copies of beloved pets.

But fears of human cloning have so far been unfounded, says a Nature editorial. “The success rate is too low to consider the method in humans, and the risk of anomalies resulting from the process is too high.” It suggests that Dolly’s greatest legacy might have been a better system for preparing for the social impact of genetic and reproductive technologies, a promise that has yet to be fulfilled.

Metro | 5 minute read and nature editorial | 7 minutes of reading

Reference: Nature paper (since 1997)

The 11 British ships that brought the first European settlers to Australia in 1788 also brought smallpox, new research suggests, and their impact was enormous. Researchers modeled the spread of the disease and found that the outbreak originated with the “First Fleet,” perhaps from material brought in to inoculate against the disease. A second modeling study suggests that the continent could have been home to more than 2.5 million people at the time, meaning that the colonial invasion led to the deaths of almost 2.4 million people.

Science | 10 minutes of reading

Reference: Research Square Preprint 1 and Research Square Preprint 2 (Not Peer Reviewed)

Climate change is making heat waves more frequent, longer and more intense, and heat is the deadliest type of weather. New scientist lays out the facts about extreme heat in five charts that show why heat is so dangerous and what cities can do to adapt.

New scientist | 6 minute read (free registration required)

Image of the week

This fossil of a 4-million-year-old tapir (Tapirus arvernensis) excavated in Spain is one of the best preserved skeletons of the species, which became extinct 2.6 million years ago.

See more of the best science photos of the month, selected by NatureThe photography equipment. (Gérard Campeny/IPHES-CERCA)

Features and opinion

A growing number of ambitious clinical trials aim to pinpoint the effects of lifestyle factors, such as a healthy diet and social stimulation, on reducing a person’s risk of dementia. So far, the data suggest that even intensive interventions help only slightly and none have reduced the incidence of dementia. But some researchers argue that any reduction in cognitive decline is worth the effort of implementing such programs. Others worry that research focuses too much on personal responsibility when risk factors such as air pollution and access to education are largely outside people’s control.

Nature | 12 minute read

Exposure to many dementia risk factors, such as physical inactivity or alcohol consumption, may have occurred over decades, and it is unclear whether changing them in midlife will undo the damage that has already been done.

The Hubble space telescope should remain operational as long as technically possible to continue collecting invaluable data about the Universe, argues astrophysicist Rogier Windhorst. Keeping Hubble active in its fifth decade will require NASA to boost the telescope to a higher, more stable orbit. Any viable option to allow this deserves serious consideration, Windhorst writes. “Scientific progress depends on both continuity and innovation.”

Nature | 5 minutes of reading

“It is quite difficult to publish a scientific case report about a grandmother who reaches 88, but if she reaches 122, you could even publish a book,” notes researcher Saul Justin Newman in his book. Morbidwhose goal is to discredit the modern science of longevity. He argues that the field is plagued by questionable data, which clouds research results and distorts policy decisions. For example, a government investigation found that 80% of Japanese centenarians on the books were missing or dead.

The New Yorker | 19 minute read

As someone who suffers from excessive mosquito attractiveness, today I was delighted with the news that a lotion with a little catnip oil appears to be as effective a repellent as DEET (north,north-diethyl-goal-toluamide). Not only can DEET be a bit strong, it is also too expensive for some of the people who need it most, and catnip (nepeta cataria) can be grown inexpensively at home. Unfortunately, I am also allergic to cats and the researchers did not test whether the lotion would attract mosquitoes and repel them at the same time.

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