CRISPR-edited chickens made resistant to a common virus

chicken

Gene edited and virus resistant

Pavel Trefil

CRISPR genome editing has been used to make chickens resistant to a common virus. The approach could boost egg and meat production worldwide while improving welfare.

The altered chickens showed no signs of disease even when exposed to high doses of the avian leukosis virus (ALV). The virus is a problem for poultry farmers around the world, says Jiri Hejnar at the Czech Academy of Sciences.

Infected birds become ill, emaciated and depressed, and often develop tumours. The virus gets into cells by binding to a protein called chicken NHE-1 (chNHE-1). Hejnar’s team has previously shown that deleting three DNA letters from the chNHE-1 gene that makes this protein prevents ALV from infecting chicken cells.

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The challenge was to make this change in entire animals rather than just in a few cells. No strains of chickens naturally have this mutation, so it can’t be done by breeding alone. But genetically modifying chickens is more difficult than modifying other animals such as pigs.

The conventional method is to extract so-called primordial germ cells, alter them outside the body and then add the modified cells to embryos inside freshly laid eggs. This approach was used to create CRISPR chickens in 2016, but the success rate is extremely low.

In 2017, Hejnar developed a better method: using altered germ cells to restore semen production in sterilised cockerels. His team then went on to create a cockerel with sperm that have the precise deletion in the chNHE-1 gene.

By crossing its offspring, they have produced a flock of white leghorn chickens that have this deletion in both copies of the gene.

A company called Biopharm is now in discussion with poultry producers in Vietnam and China about introducing this change into commercial breeds. “It’s quite simple to do,” says Hejnar.

Hejnar also plans to use CRISPR to make chickens resistant to other viruses, such as bird flu. This would make us all safer: bird flu viruses sometime kill people and there are fears a mutant strain could cause a deadly global pandemic.

However, there is still opposition to GM foods in many countries. It remains to be seen whether consumers will find CRISPR chickens to their taste.

Journal reference: PNAS, DOI: 10.1073/pnas.1913827117

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Climate change-related injuries will kill thousands in the US

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Accidental deaths in the US from drowning and car crashes may rise as the climate warms

Seastock/iStockphoto/Getty Images

The US is likely to see more than 2000 extra deaths a year from car accidents, suicide, drowning and other fatal injuries because of climate change, even if the world manages to hold temperature rises to the Paris climate deal’s target of 2°C.

Research on deaths due to climate change usually focuses on older people who might be at a higher risk of heart and lung problems. Many older people were among the estimated 35,000 people who died in the 2003 Europe heatwave. But a team led by Robbie Parks at Imperial College London has found one way in which rising temperatures will increase death rates among younger people.

The researchers examined government figures on the 6 million people who died after an injury between 1980 and 2017 in the US, excluding Hawaii and Alaska.

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Combining the data with monthly temperature spikes above the long-term average over the period, they found that in a future year that is anomalously hot by 1.5°C – the Paris accord’s toughest target – there will be 1601 extra deaths from injuries each year. If temperatures rise by the worst-case Paris goal of 2°C, the number climbs to 2135.

Car crashes

“Climate change as a health issue goes beyond the physical and goes to the behavioural and the mental,” says Parks, who says the projected increase in deaths isn’t insignificant.

Notably, the extra deaths would fall overwhelmingly – 84 per cent – on men, with most of them aged between 15 and 64. The biggest number of extra deaths would be related to transport, such as car crashes, followed by suicide. There will also be a smaller rise in deaths from drowning.

The study doesn’t show why younger men will be affected more, but it may be down to more reckless behaviour causing unintentional deaths such as drowning, says Parks.

The total number of extra deaths is relatively small: 2135 deaths equates to 1 per cent of all injury-related deaths in the US. But Parks says that the way the deaths fall on otherwise young and healthy men would have knock-on effects, including on the economy.

“It is concerning that most of these injury-related deaths are expected to occur among young adults,” says Francesca Dominici at Harvard University. Moreover, she expects there may be an even higher death toll when other factors are considered, such as accidental deaths linked to wildfires during heatwaves.

The risk of more deaths can be reduced by cutting carbon emissions and limiting future warming, and by public health efforts, such as targeting young men with campaigns about the risks of drowning, says Parks.

Journal reference: Nature Medicine, DOI: 10.1038/s41591-019-0721-y

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Gravitational wave mystery could be a sign of a new kind of black hole

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Alfred Pasieka/Science Photo Library

A strange set of gravitational waves have been sent across space by a mysterious object. It could be the smallest black hole ever found or the largest neutron star.

Gravitational waves are ripples in space time that are caused by the motion of massive objects. The Laser Interferometer Gravitational-Wave Observatory (LIGO) has detected these waves from many pairs of black holes colliding over the last few years, as well as one pair of neutron stars.

Now they have found a truly puzzling collision, said LIGO team member Katerina Chatziioannou at a meeting of the American Astronomical Society in Hawaii on 6 January. A LIGO detector in Louisiana spotted signs of two objects colliding, but nobody is quite sure what one of the objects is.

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In this smash-up, one of the objects was definitely a neutron star with a mass between 1.1 and 1.7 times the mass of the sun. While the other object is probably also a neutron star, months of analysis have not been able to prove it is, says LIGO team member Nelson Christensen.

Its mass could be as high as 2.5 times that of the sun, which means it could be massive enough to be a black hole.

“We’ve never seen any neutron star with this large a mass,” says Christensen. “The question is, is it really a neutron star? If it is, then we’ve detected a really strange heavy neutron star, but if it’s a black hole it’s a really light black hole.”

While the idea of such a low-mass black hole is plausible, the lightest one anyone has found thus far is 3.3 times the mass of the sun. If it is not the smallest black hole ever found, but in fact a neutron star, this object is still unusual because it’s not clear how a neutron star with a nearby partner could get so large.

“It’s clearly heavier than any other pair of neutron stars ever observed,” said Chatziioannou in a press conference. “The existence of a system like that challenges our current understanding of how those systems form binaries and merge to give off gravitational waves.”

We should get used to this kind of strange discovery, says Christensen. “We’re getting about one gravitational wave event a week now, and that’s a lot,” he says. “With a lot of events you inevitably see cool stuff every now and then.”

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Scientist behind world’s first gene-edited babies sentenced to prison

He Jiankui attempted to make babies resistant to HIV

He Jiankui attempted to make babies resistant to HIV

Visual China Group via Getty Images

The scientist behind the birth of the world’s first gene-edited babies has been sentenced to three years in prison. He Jiankui, who announced he had used CRISPR technology on embryos that led to two births in 2018, has also been fined 3 million yuan, equivalent to about $430,000, according to Chinese state news agency Xinhua.

On Monday 30 December, a court in Shenzen found that He and his colleagues forged ethical review materials, violated national regulations on scientific research and medical management and caused harm to society, according to the report. Two of He’s colleagues, Zhang Renli and Qin Jinzhou, have also been given prison sentences and fines.

All three pleaded guilty in a private trial. They also face a lifelong ban on engaging in any human assisted reproductive technology services and some scientific research projects.

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Robin Lovell-Badge at the Francis Crick Institute in London told the UK Science Media Centre that a prison sentence and fine would also have been the likely penalties if someone had conducted similar work in the UK.

Widespread controversy

The birth of two gene-edited twin girls was announced by He at a conference in 2018, days after news reports revealed the first details of his experiments. He claimed to have used CRISPR gene editing technology to disable a gene for a protein that the HIV virus binds to. His team hoped that the babies would be born resistant to HIV.

The team created 22 embryos using cells from seven couples, and 16 appeared to have been successfully gene edited. Eleven were implanted into women, with one woman becoming pregnant.

There were other issues with the experiment. All of the fathers in the study were HIV positive, but this doesn’t mean that they would have passed the infection to their children – HIV transmission can be controlled with simple medical measures, with no need for experimental genetic techniques. And there are concerns that CRISPR can have unpredictable effects on other genes.

He’s work was widely denounced by the scientific community. He lost his job at the Southern University of Science and Technology in Shenzen in January 2019, after an investigation by the Health Commission of China in southern Guangdong province found that he had “illegally conducted the research in the pursuit of personal fame and gain”.

Back in 2018, He mentioned that a second woman had since become pregnant. The court report confirms that two women became pregnant with gene-edited babies, and that, in total, three have been born.

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We’ve found six scorchingly hot exoplanets that are over 1100°C

An artist’s visualisation of a planet orbiting star DMPP-2

An artist’s visualisation of a planet orbiting star DMPP-2

Mark A. Garlick

We have discovered six new exoplanets by looking at hot gas nearby. Carole Haswell at the Open University in the UK and her colleagues made the discovery by studying nearby stars that the exoplanets orbit.

The six exoplanets are all extremely hot, with temperatures of between 1100°C and 1800°C. They range in mass from around 2.6 times the mass of Earth up to almost half Jupiter’s mass.

Some exoplanets are located much closer to their stars than planets in our solar system are to …

Anti-ageing drug rejuvenates the mouths and oral microbiome of mice

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The bones around mouse teeth like this one were rejuvenated by anti-ageing drugs

STEVE GSCHMEISSNER / SCIENCE PHOTO LIBRARY

A transplant drug with anti‑ageing properties has been shown to rejuvenate the oral health of old mice. The drug, called rapamycin, regenerated the bone in which teeth are embedded, restored the mouth microbiome to a youthful state and reduced inflammation.

It is the first time any treatment has been shown to rejuvenate oral health, says team leader Matt Kaeberlein at the University of Washington in Seattle. “We could actually see spots where new bone was growing around the teeth.”

Two-thirds …

We finally know how whole planets grow from tiny clumps of dust

dust clouds in space

Planets in the making?

NASA/JPL-Caltech

Electricity may be more important to making planets than we thought. We aren’t sure how tiny particles come together to build baby planets, but dropping glass beads from the top of a tall tower has shown that it may be with some help from static electricity.

The very first seeds of planets are made of micrometre-sized grains of dust, which bump into one another as they orbit a star and stick together in fluffy clumps. As more and more tiny grains stick together, the clumps start to compact, until they are no longer fluffy and start to bounce off one another like billiard balls instead of sticking. This happens when the clumps are millimetres across and is called the bouncing barrier.

In order to build a planet, those millimetre-sized dust bunnies have to overcome the bouncing barrier and get bigger. It has been suggested in the past that this may be enabled by static electricity – as the dust particles collide and rub together, they gain electric charges that can encourage them to stick together.

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Tobias Steinpilz at the University of Duisburg-Essen in Germany and his colleagues investigated this using the Bremen drop tower, a hollow turret about 120 metres high that acts as a vacuum chamber in which falling objects behave like they would in the microgravity of space.

They used the tower’s built-in catapult to throw a chamber containing 0.4-millimetre glass beads up towards the top of the tower, then allowed it to fall, watching it with a high-speed camera installed within the falling chamber. They found that the beads did gain electrical charge from static electricity and stuck together in clumps up to several centimetres across.

“When you have charged particles and they form centimetre-sized clusters like we observed in our experiments and our simulations, we can close this gap in size caused by the bouncing barrier,” says Steinpilz. The particles are then free to clump together even more with the help of gravity and eventually become planets.

Journal reference: Nature Physics, DOI: 10.1038/s41567-019-0728-9

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The race to find wild relatives of food plants before it’s too late

The Millennium Seed Bank

Kew’s Millennium Seed Bank

Kew

Seeds from 400 wild relatives of food crops such as bananas, rice and aubergines have been collected to save their valuable genetic diversity before it is lost. These could be crucial for maintaining food production as the climate changes.

“This was a massive effort,” says Hannes Dempewolf at the Crop Trust in Bonn, Germany, which led the 10-year project. The next step is to use the wild plants to breed new varieties of crops with traits such as drought or disease resistance.

That is important because we know that if farmers keep cultivating the same varieties in the same way, yields can plummet as pests and diseases evolve and spread. For instance, rice yields in Asia were hit by the rice grassy stunt virus in the 1970s, says Dempewolf. Resistant varieties were then created by crossing rice with a wild relative. Now the virus is becoming a problem again. It is a constant battle, a bit like walking up an escalator the wrong way.

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What is more, the speed at which such issues arise is accelerating because of climate change, which is already hitting food production. “You have to walk faster to stand still,” says Alisdair Fernie of the Max Planck Institute for Molecular Plant Physiology in Germany, who wasn’t involved in the project.

Treasure trove

This is why the Crop Trust set out to save the genetic diversity present in wild plants. “Since 2013, more than 12 million seeds have been collected,” says Chris Cockel at Kew’s Millennium Seed Bank in the UK. These come from about 5000 locations of the 400 crop relatives.

Plants sampled include a wild relative of the carrot, one that grows in salty water, an oat relative resistant to the powdery mildew that devastates normal oats, and a kind of bean that tolerates high temperatures and drought.

The seeds are now being sent to non-profit breeding organisations around the world. Some will also be stored in seed banks, including the Svalbard Global Seed Vault in the Arctic.

In some cases, the collectors arrived in the nick of time. In Ethiopia, samples were taken from a region that will soon be flooded by a dam. In Chile, they found only one site where a wild barley was still growing after a massive fire destroyed most of its habitat.

Sometimes they were too late. In Costa Rica, collectors found only sugar cane plantations and urban sprawl where a wild rice used to grow.

Read more: Domesticating tomatoes took millennia – we can now redo it in 3 years

“We have made incredible progress,” Marie Haga, director of the Crop Trust, said in a statement. “But there is more to be done, and as threats to the world’s biodiversity mount, this work is more urgent than ever.”

As well as improving existing crops, we should also be conserving and domesticating wild plants that are rarely grown and eaten, says Fernie. At present the world is over-reliant on a handful of crops, some of which are grown where conditions aren’t ideal.

In these places, domesticating local plants – which can now be done very rapidly – could allow more food to be grown in a more sustainable way. But for farmers to diversify the plants they grow, consumers will have to diversify their diets.

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Controversial DNA screening technique used for at least one pregnancy

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DNA can be taken from IVF embryos and analysed

PASCAL GOETGHELUCK/SCIENCE PHOTO LIBRARY

A company called Genomic Prediction has confirmed that at least one woman is pregnant with embryos selected after analysing hundreds of thousands of DNA variants to assess the risk of disease. It is the first time this approach has been used for screening IVF embryos, but some don’t think this use of the technology is justified.

“Embryos have been chosen to reduce disease risk using pre-implantation genetic testing for polygenic traits, and this has resulted in pregnancy,” Laurent Tellier, CEO of Genomic Prediction, told New Scientist. He didn’t say how many pregnancies there were, or what traits or conditions were screened for.

While a few genetic mutations lead to serious disorders, the effect of most DNA changes is much less clear-cut. A particular mutation may only very slightly raise the risk of heart disease or cancer, for instance. Geneticists attempt to work out the overall effect of thousands of mutations by sequencing people’s DNA and calculating a so-called polygenic risk score, but there are big questions about how accurate or useful these are.

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Genomic Prediction, which is based in New Jersey, is the first company to offer polygenic risk scores for embryos rather than adults, including an option to screen out embryos deemed likely to have very low IQ.

Using polygenic risk scores to screen embryos is controversial. “It is inappropriate to use pre-implantation genetic diagnosis to screen out polygenic risk factors for things like cardiovascular disease,” says Frances Flinter at Guy’s and St Thomas’ NHS Foundation Trust in the UK. “I think it’s a misuse of the technology.”

Such screening places undue emphasis on genetics when it isn’t the biggest factor, she says. For most of us, our risk of heart disease is determined by our diet, whether we smoke, how much exercise we take and so on.

“It’s completely different from using pre-implantation genetic diagnosis to select out embryos at high risk of a very serious disorder, when we can predict with complete accuracy whether or not those embryos will be affected,” says Flinter.

But Steven Hsu, one of the founders of Genomic Prediction, says polygenic scores reveal that a few people – those with the top 3 per cent of scores – have a dramatically higher risk of, say, breast cancer or heart disease. The company’s tests aim to identify these outliers.

“These results are very new,” says Hsu. “A typical pre-implantation genetic diagnosis expert who focuses on single gene conditions might not be aware of how strong the polygenic predictions can be.”

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Robot debates humans about the dangers of artificial intelligence

Project Debater

Project Debater argued both for and against the benefits of artificial intelligence

IBM

An artificial intelligence has debated the dangers of AI – narrowly convincing audience members that the technology will do more good than harm.

Project Debater, a robot developed by IBM, spoke on both sides of the argument, with two human teammates for each side helping it out. Talking in a female American voice to a crowd at the University of Cambridge Union on Thursday evening, the AI gave each side’s opening statements, using arguments drawn from more than 1100 human submissions made ahead of time.

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On the proposition side, arguing that AI will bring more harm than good, Project Debater’s opening remarks were darkly ironic. “AI can cause a lot of harm,” it said. “AI will not be able to make a decision that is the morally correct one, because morality is unique to humans.”

“AI companies still have too little expertise on how to properly assess datasets and filter out bias,” it added. “AI will take human bias and will fixate it for generations.”

Read more: The hardest thing about robots? Teaching them to cope with us

The AI used an application known as “speech by crowd” to generate its arguments, analysing submissions people had sent in online. Project Debater then sorted these into key themes, as well as identifying redundancy – submissions making the same point using different words.

Project Debater

Project Debater summarised arguments put forward by humans

IBM

The AI argued coherently but had a few slip-ups. Sometimes it repeated itself – while talking about the ability of AI to perform mundane and repetitive tasks, for example – and it didn’t provide detailed examples to support its claims.

While debating on the opposition side, which was advocating for the overall benefits of AI, Project Debater argued that AI would create new jobs in certain sectors and “bring a lot more efficiency to the workplace”.

But then it made a point that was counter to its argument: “AI capabilities caring for patients or robots teaching schoolchildren – there is no longer a demand for humans in those fields either.”

Read more: Want to build robots and invent stuff? Here’s where to start

The pro-AI side narrowly won, gaining 51.22 per cent of the audience vote.

Project Debater argued with humans for the first time last year, and in February this year lost in a one-on-one against champion debater Harish Natarajan, who also spoke at Cambridge as the third speaker for the team arguing in favour of AI.

IBM has plans to use the speech-by-crowd AI as a tool for collecting feedback from large numbers of people. For instance, it could be used by governments seeking public opinions about policies or by companies wanting input from employees, said IBM engineer Noam Slonim.

“This technology can help to establish an interesting and effective communication channel between the decision maker and the people that are going to be impacted by the decision,” he said.

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