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Stone statues on Easter Island.Credit: Gregory Boissy/AFP/Getty
Polynesians and South Americans made contact around AD 1200
Traces of Native American ancestry have been found in the genomes of modern inhabitants of some Polynesian islands, suggesting that ancient islanders met and mixed with people from South America hundreds of years ago. Researchers analysed the genomes of more than 800 people from 17 Pacific islands and 15 Native American groups on the Pacific coast. The team looked at the length of shared DNA segments — which shorten in successive generations — to determine that people from Polynesia and South America mingled around 800 years ago (before Europeans began colonizing either region). Whether Polynesians voyaged to the coast of the Americas, or people from South America made the trip to the islands, is still up for debate.
US crackdown harming China collaborations
Scientists in China say they’re reluctant to travel to the United States when pandemic restrictions lift, and some are even reducing their e-mail and phone communication with US researchers. They fear being caught up in the US government crackdown on foreign interference in science. Dozens of researchers — many with ties to China — have been fired or have resigned amid allegations that they breached government-agency rules or those of their institutions, mostly to do with disclosing foreign ties or conflicts of interest. Researchers in both countries say this fear — as well US policies to restrict visas to some students and scholars from China — is impacting collaborations.
Precise edits to mitochondrial DNA
A peculiar bacterial enzyme has allowed researchers to achieve what even the popular CRISPR–Cas9 genome-editing system couldn’t manage: targeted changes to the genomes of mitochondria, cells’ crucial energy-producing structures. The technique could allow researchers to develop new ways to study, and perhaps even treat, diseases caused by mutations in the mitochondrial genome. “It’s an amazing step forward,” says mitochondrial geneticist Michal Minczuk.
COVID-19 coronavirus update
As restrictions are lifted, many researchers worry that the risk of catching COVID-19 will go up in crowded indoor spaces.Credit: Anthony Devlin/Getty
Mounting evidence for airborne spread
Evidence is building that the SARS-CoV-2 coronavirus can pass from person to person in tiny droplets called aerosols that waft through the air and accumulate over time. But this conclusion is not popular with some experts, because it contravenes evidence from decades of research into respiratory infections. On Monday, scientists urged authorities to acknowledge the potential for airborne transmission, in a commentary signed by 239 clinicians, infectious-disease physicians, epidemiologists, engineers and aerosol scientists. They also call for preventive measures to reduce this type of risk. In response, the World Health Organization will issue new guidelines about transmission in settings with close contact and poor ventilation.
Reference: Clinical Infectious Diseases paper
Moderna spars with US-government scientists
One of the leading vaccine candidates for COVID-19 would be progressing even faster if not for tensions between biotechnology firm Moderna and US-government scientists over protocols, reports Reuters. Moderna has never produced a government-approved vaccine before. Moderna acknowledged “differences of opinion” to Reuters, but denied any missteps.
What school openings worldwide reveal
Countries around the world have reopened schools post-lockdown, walking a tightrope between stopping the spread of COVID-19, aiding working parents and supporting children’s well-being inside and outside the classroom. Science digs deep into “a vast, uncontrolled experiment” in which the data are scarce and the stakes are high.
Features & opinion
Senior engineer Muna Al Hammadi discusses plans with other engineers in one of The Mohammed Bin Rashid Space Centre laboratories.Natalie Naccache for Nature
How the UAE built a Mars mission
The United Arab Emirates (UAE) plans to launch its Mars-orbiter mission sometime during a three-week window starting on 15 July. It’s been a mere six years since the nation announced the project, which it hopes will help to transform its oil economy into a knowledge economy. Fundamental to the mission was tapping the expertise of seasoned US engineers, who helped to build the craft and train their UAE counterparts. The mission’s Emirati team personifies the aspiring scientists that the project hopes to inspire: at its outset, the average age of the engineers was 27, and women make up 80% of its scientists. If the UAE can pull off that economic transformation, it would be an even greater prize than getting to Mars, says Sarah Al Amiri, the science lead for the project and the country’s minister for advanced sciences. “How we get there is even more important,” she says.
Past outbreaks show how to support women
In disease outbreaks, women bear the brunt of the social and economic effects. For example, during the Ebola outbreak of 2014–16, quarantines destroyed the livelihoods of market traders in Sierra Leone and Liberia, 85% of whom were women — and a far smaller proportion of women than men were back at work by the following year. Clare Wenham, who researches global health policy, and seven colleagues call for COVID-19 support and research tailored to women’s right to work, be free of domestic violence and access sexual- and reproductive-health care.
Reference: World Bank working paper
For a start, let’s pull carbon from the sky
Scientists have provided the most detailed analysis yet of the technical and economic potential of sequestering carbon by speeding up the natural weathering process of silicate rocks. In ‘enhanced rock weathering’, minerals such as basalt could be spread over croplands — potentially boosting crop yields and soil health at the same time. It’s not a substitute for aggressive action to cut emissions, notes a Nature editorial, and there will be environmental, regulatory and practical challenges. “But it is becoming clear that if humanity is to limit global warming to 1.5–2 °C above pre-industrial levels, it must pursue every promising idea.”
Reference: Nature paper
2 billion tonnes
The amount of CO2 that could potentially be removed from the air each year if the world’s biggest economies added basalt dust to their agricultural land — akin to offsetting emissions from around 500 coal-fired power plants.
