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DNA dogma

Francis Crick (c) Cold Spring Harbor LaboratoryImage copyright
Cold Spring Harbor Laboratory

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Crick’s lecture was said to have altered the logic of biology

Sixty years ago this week, one of the greatest British scientists, Francis Crick, gave a lecture in London in which he accurately predicted how genes work, setting the course for the genetic revolution we are now living through. Here, evolutionary biologist Professor Matthew Cobb from Manchester University unpicks the predictions that set a new course for how we understand the very stuff we are made from.

In one lecture, it has been said that Francis Crick “permanently altered the logic of biology”.

Only four years earlier, he and the young American Jim Watson had solved the double helix structure of DNA, using data gathered by Rosalind Franklin. Aged 41, Crick was still five years away from winning the Nobel Prize for this work, but he had a reputation as a powerful and profound thinker.

He gave his lecture – “On protein synthesis” – at University College London for the Society for Experimental Biology. In it, Crick spoke about how genes do what they do. At the time, this subject was still very murky – some scientists were not even convinced that genes were made of DNA.

But Crick delivered four predictions about genes – and their link to the proteins that build our bodies. In each of these ideas, he was right.

Cracking the code

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Science Photo Library

Crick started with the main thing that genes do: they control the production of proteins.

The problem Crick explored was that the DNA in a gene is simply a chemical code – a string of something called bases – A, C, T, G.

Crick had to explain how the cell could get from this one-dimensional sequence of bases in DNA to the complex three-dimensional structures of proteins. Even more puzzling was the fact that proteins can fold themselves into nearly any shape.

Crick’s answer was simple: the order of bases in the gene – what he called “genetic information” – corresponded to the order of the amino acids that make up each protein, and nothing more.

There was no structural information about the protein that was encoded in the gene, he claimed. He called this the sequence hypothesis.

Somehow, the cell “read” the information in the gene and assembled the amino acids together like beads on a string. The resulting protein folded itself – spontaneously – into its final 3-D structure. We still cannot easily predict the structure of a protein from the order of its amino acids, but Crick’s sequence hypothesis holds good.

Central dogma

To explain how exactly cells assemble proteins, Crick predicted there must be some small molecules – he called these “adaptors” – that could recognise each of the 20 different amino acids in the body, and would bring them to where they could be turned into a protein in the right order.

As Crick gave his talk in London this molecule was being identified in an American laboratory. It is now called transfer RNA. It is the biological messenger that reads and “translates” the genetic code in the cell’s protein-building factory.

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Wellcome Library, London

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Crick drew a diagram to explain the flow of information from DNA to proteins

The most controversial and influential part of the lecture though was what was called the central dogma. Crick explained that as proteins are synthesised, information is taken from the DNA molecule, first into an RNA molecule, and is then used to make a protein.

Before the lecture, he drew a little diagram to explain what he meant. The arrows show what Crick called the flow of information going from DNA to RNA to protein. DNA and RNA could also copy themselves, so there are also arrows going from DNA to DNA and from RNA to RNA.

Because the experimental data were not clear, Crick accepted that it might just be possible that DNA could directly lead to the production of proteins, so he drew an arrow there, too (this is not in fact the case).

The most important point was that, as Crick put it, once the information had gone from DNA into a protein, it could not get back into your DNA. There was no biochemical route for a protein to change your DNA sequence.

Crick thought it might be possible for information to go from RNA to DNA, and this later turned out to be the case, when it was discovered that some RNA viruses can get into our DNA. But the route from protein to DNA is impossible.

This central dogma emphasises that our DNA sequence cannot be changed by our proteins, or by how they are changed by experience. Over the last 60 years this has proved to be correct. Despite the excitement about what is called epigenetics, which explains how genes can be turned on and off by the environment, this never leads to a change in our actual DNA sequence. Crick’s dogma was absolutely right.

Crick later cheerfully admitted that when he coined the phrase, he didn’t know what a dogma was. What he really meant was that it was a basic assumption about how genes worked. Whatever its name, it still guides scientists today.

Crick’s final brilliant prediction was to suggest that in the future biologists would use sequence data to understand evolution, by comparing the sequences of different species.

In 1957, when Crick was speaking, protein sequences were known from only five species, while DNA sequencing was science fiction and 20 years in the future. But this is exactly what happened, and we can now understand how organisms evolved in unprecedented detail, by comparing their sequences, just as Crick suggested.

Crick’s lecture, which was published the following year, continues to be read and cited by scientists all over the world. It is a monument of clear and penetrating thinking by one of the 20th century’s greatest minds. In all his key predictions, Francis Crick was right, and he did indeed change the logic of biology.

Professor Matthew Cobb is a zoologist, historian and author based at Manchester University

Article source: http://www.bbc.co.uk/news/science-environment-41311087

The winners of 2017′s Insight Astronomy Photographer award

The winners have been announced for the Insight Astronomy Photographer of the Year. The competition received 3,800 entries from amateurs and professional photographers from all over the world.

One of the judges is Dr Marek Kukula. He tells Dan Damon about the dreamers and scientists behind the images.

(IMAGE CREDIT: The Rho Ophiuchi Clouds © Artem Mironov (Russia) – STARS NEBULAE WINNER OVERALL WINNER.)

Article source: http://www.bbc.co.uk/news/world-41352399

Bright sparks

installation of a solar panelImage copyright
Getty Images

The US solar industry has seen dramatic growth in the past few years, but a request for a rare trade action has led to a fierce fight over the future of the industry – and one that wouldn’t exist without the presidency of Donald Trump.

Phil Brodhagen runs a solar installation company in Colorado Springs, and his customers – local homeowners and businesses in a military-friendly town – love American-made products.

Until they see the price.

“They want to go solar, but they do have a limit on how much they can spend.” he says. “They’d love an American product, but if they can’t afford it, they’ll either not get a system at all, or go for the cheaper one.”

Brodhagen is one of hundreds of business owners across the US paying very close attention to a case in front of the US International Trade Commission. And he’s worried about the outcome.

“It will hurt this industry,” he says. “It’s going to be me laying off people as well as everyone else.”

On Friday, the commission is expected to rule on whether imported solar products have seriously injured US solar product manufacturers, enough to impose higher tariffs on imports worldwide.

The petition was brought by two solar manufacturers who are based in the US, but owned by overseas companies.

Suniva and SolarWorld have argued their financial troubles – as well as a series of other US solar manufacturer bankruptcies – are due to a massive oversupply of solar cells and panels imported from overseas, primarily from Chinese companies.

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Getty Images

They point to dozens of US companies like theirs that have gone out of business since 2012.

“Quite simply, we need the commission’s help to save solar manufacturing in the United States,” Juergen Stein, chief executive of SolarWorld Americans told the commission in August.

But SolarWorld and Suniva find themselves fiercely opposed by much of the solar industry in the US, including the largest trade group, the Solar Energy Industries Association (SEIA).

SEIA has argued increasing the prices of panels through tariffs will set back the solar industry for years, hurting companies that buy and install solar panels, or make solar-related products. The trade group estimates a loss of as many as 88,000 jobs, or a third of the current solar work force, if Suniva and SolarWorld’s requests come to pass.

The group accuses the two companies of using the rare trade action to save themselves, at the expense of the rest of the industry.

What’s at stake? For both sides, the immediate future of the fast-growing solar industry in America.

Bret Sowers, a utility-scale solar farm developer, calls the trade case an “eminent threat” to his business. Projects like his are reliant on how low a price per watt cost they can offer utility firms. Their competition is not just other solar firms, but coal and wind, natural gas and nuclear energy.

New solar capacity doubled between 2015 and 2016 and such large-scale projects drove more than half the growth.

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Reuters

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An employee makes a final inspection on panels during a tour of an REC solar panel manufacturing plant in Singapore

“We have close to $2bn in investment we’ve planned across the southeast,” he says, based on prices continuing their downward trend. If he can’t deliver the prices he expected, those solar farms won’t be built.

“That’s hundreds of construction jobs gone,” he says, and layoffs at his company.

Sowers is specifically frustrated because US plants at SolarWorld and Suniva were not building the larger, 72-cell panels at the kind of scale his projects need.

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“The two dots don’t really connect. They were making cars and I’m buying trucks – and now they’re claiming the trucks are hurting the cars.”

James Marlow, who runs a similar Georgia company, is frustrated with the petition, even though he just finished a project with Suniva panels.

“They used to be the home town team,” he says of the firm, originally spun out from Georgia Tech and headquartered in the state.

In 2015, in an effort to expand, a Hong Kong-based energy firm purchased more than half the company, but Suniva filed for bankruptcy earlier this year, and weeks later, brought the trade petition.

SolarWorld, whose parent company also filed for insolvency in Germany, joined the petition shortly thereafter.

Marlow says he supports bringing back manufacturing to America, but thinks that means a whole set of policies to deal with what’s a “drastically larger” issue.

“It’s why most of our clothes are made in Asia and why this cell phone I’m talking to you on made in Asia – it’s not just one action.”

Media captionA stretch of road has been paved with solar PV (photovoltaic) panels in France.

He attended the 15 August arguments in front of the trade commission on the case and said interest was intense. There were two overflow rooms for people to listen. An official told him they hadn’t seen that many people come to hear a case since NAFTA.

If the trade commission finds in favour of the manufacturers, it can make recommendations, but it is up to the president to decide.

And President Trump is eager to impose tariffs, especially in an industry in which he could be seen to be tough on Chinese manufacturing. He reportedly has said “I want someone to bring me some tariffs” because “China is laughing at us”.

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Getty Images

Once the trade commission makes its initial ruling, it will have several more weeks to make a recommendation to Trump. The president then can decide to take the recommendation or not.

Solarworld had earlier successes with two requests for increased tariffs on Chinese manufacturers for similar unfair trade practice accusations.

But that wasn’t enough, says Tim Brightbill, a lawyer representing SolarWorld, because Chinese firms shifted production to other countries to get around the tariffs.

He also claims the potential job loss numbers are overblown.

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“These predictions were made before when SolarWorld brought actions against China, that somehow jobs would be lost. But the opposite happened,” Brightbill says.

The situation is especially odd considering both SolarWorld and Suniva are owned by parent companies that could be harmed by the tariff.

Brightbill says “it just shows that SolarWorld is committed to manufacturing here,” even if it involves putting a tariff on a German-produced panel.

They may not be alone. While the US solar industry is holding its breath, foreign manufacturers are starting to think about setting up shop in the US, especially if the commission recommends a broad tariff.

Both sides see the dispute as a turning point for the industry – and both think the president should be on their side.

“If the Trump administration wants to create jobs,” James Marlow says. “They should join with the solar industry.”

The question for President Trump will be – which part?

Article source: http://www.bbc.co.uk/news/world-us-canada-41352259

How killer flies have the fastest vision of any animal

Flies are notoriously hard to swat because they see around four times faster than humans. They effectively watch you coming in slow-motion. In fact, scientists discovered that so-called ‘killer flies’ have the fastest vision of any animal.

Find out more with CrowdScience: Spider silk and super fly senses.

Article source: http://www.bbc.co.uk/news/science-environment-41287217

‘We are planning weekly rocket launches’

The small satellite industry is the fastest growing part of the space sector “and they all require launch” says New Zealand’s Rocket Lab boss Peter Beck. His firm aims to disrupt the established space sector by launching its commercial satellite-carrying rockets once a week.

Find out more at The Disruptors #thedisruptors @BBCMoney

Producer: Adrienne Murray; Cameraman: Mauricio Olmedo-Perez

Article source: http://www.bbc.co.uk/news/business-40940723

How business is driving the new space race

The space race of the Cold War pitted the world’s two superpowers against one another to explore what lies beyond Earth.

Now anyone with enough money and enterprise can get there. But this new race isn’t between countries – it’s between companies.

Find out more at The Disruptors #thedisruptors @BBCMoney

Producer: Philippa Goodrich; Reporter: Tim Bowler

Article source: http://www.bbc.co.uk/news/business-40940721

UK scientists edit DNA of human embryos

Embryo genetically modifiedImage copyright
Kathy Niakan

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The genetic machinery needed to modify the DNA is injected into the embryo

The blueprint for life – DNA – has been altered in human embryos for the first time in the UK.

The team at the Francis Crick Institute are unravelling the mysteries of the earliest moments of life.

Understanding what happens after a sperm fertilises an egg could lead to ways of improving IVF or explain why some women miscarry.

The embryos were modified shortly after fertilisation and allowed to develop for seven days.

The researchers are exploring one of the most astounding of transformations.

We have all journeyed from a single fertilised egg to a human being – built from myriad different tissues ranging from bone to those needed to read this page.

The first few steps on that journey are as critical as they are poorly understood.

Image copyright
Kathy Niakan

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The embryo divides and develops from a single fertilised egg (top left) to a blastocyst (bottom right)

Breakthroughs in manipulating DNA have allowed the team at the Crick to turn off a gene – a genetic instruction – suspected to be of vital importance.

The easiest way of working out how something works is to remove it and see what happens.

So the researchers used the gene-editing tool Crispr-Cas9 to scour the billions of letters of genetic code, find their genetic target and break the DNA to effectively disable it.

They were targeting a gene. You are unlikely to have heard of it, but OCT4 is a superstar in early embryo development.

Its complete role is not understood but it acts like an army general issuing commands to keep development on track.

The researchers used 41 embryos that had been donated by couples who no longer needed them for IVF.

After performing the genetic modification, the team could watch how the embryos developed without OCT4.

Media captionIn a first for UK scientists, human embryos have been genetically modified.

Over the course of the first seven days, a healthy, normal embryo goes from one cell to about 200. It also goes through the first steps of organising itself and handing out specialised jobs to different cells.

The embryo forms a hollow sphere called a blastocyst, with some cells destined to go on to form the placenta, some the yolk sac and others, ultimately, us.

But without OCT4 the blastocyst cannot form. It tries – but implodes in on itself.

From the embryo’s perspective it is a disaster but for scientists it has given unprecedented insight.

Image copyright
Kathy Niakan

Image caption

The cells coloured green in the blastocyst have high levels of OCT4 and are the ones that go on to form the human body

It is the first time human embryos have been edited to answer questions about fundamental biology.

Dr Kathy Niakan, a group leader at the Crick in London, told the BBC: “When it seemed it was working we were quite excited about the possibility that this would open up.

“This is basic research which is providing us with a foundation of knowledge about early human development.”

By deepening understanding of the earliest moments in life, it could help explain what goes wrong in infertility.

During IVF, of 100 fertilised eggs, fewer than 50 reach the blastocyst stage, 25 implant into the womb and only 13 develop beyond three months.

This study alone, published in the journal Nature, cannot explain what is going wrong or why some women miscarry.

But by interrogating all the genes suspected of playing a role in our inception, it could lead to new advances.

Image copyright
crick institute

Image caption

Dr Kathy Niakan in the Crick laboratories where the embryos were modified

Dr Niakan told the BBC: “If we knew the key genes for an embryo to develop successfully that would, I would hope in the future, lead to improvements in IVF technology and give us really important insights into why some pregnancies fail.”

One option for IVF is to have a better way of testing which embryos are going to be successful.

Or it may be possible to boost embryos during IVF by growing them in a different culture media – a fertiliser for fertilised eggs.

Ethical debate

These experiments have been legal since 2008 in the UK, where it is possible to manipulate such embryos for 14 days as long as they are not implanted.

But while this application of the technology is answering fundamental questions of science, other research groups are trying to remove genes that cause disease.

That is provoking deep ethical debate.

Dr Sarah Chan, a bioethicist at the University of Edinburgh, told the BBC: “I don’t think this study should raise any ethical concerns.

“It is very clear that the aim of the research was basic science and that there was never any intention to create genetically modified human beings.

“That said if we could one day use gene editing in human embryos for medical purposes, the potential benefits could be huge, but before we took such a step we would want to make sure that we’d had a really robust and wide-ranging public dialogue on all of the ethical issues involved.”

Dr Rob Buckle, the chief science officer at the UK Medical Research Council, said: “Genome editing technologies are having a game-changing effect on our ability to understand the function of critical human genes.

“As genome editing techniques develop it’s vital that this work continues within a robust yet adaptable regulatory framework so that its full potential can be realised in a scientific, ethical and legally rigorous way.”

Follow James on Twitter.

Article source: http://www.bbc.co.uk/news/health-41269200

New antibody attacks 99% of HIV strains

HIVImage copyright
SPL

Scientists have engineered an antibody that attacks 99% of HIV strains and can prevent infection in primates.

It is built to attack three critical parts of the virus – making it harder for HIV to resist its effects.

The work is a collaboration between the US National Institutes of Health and the pharmaceutical company Sanofi.

The International Aids Society said it was an “exciting breakthrough”. Human trials will start in 2018 to see if it can prevent or treat infection.

Our bodies struggle to fight HIV because of the virus’ incredible ability to mutate and change its appearance.

These varieties of HIV – or strains – in a single patient are comparable to those of influenza during a worldwide flu season.

So the immune system finds itself in a fight against an insurmountable number of strains of HIV.

Super-antibodies

But after years of infection, a small number of patients develop powerful weapons called “broadly neutralising antibodies” that attack something fundamental to HIV and can kill large swathes of HIV strains.

Researchers have been trying to use broadly neutralising antibodies as a way to treat HIV, or prevent infection in the first place.

The study, published in the journal Science, combines three such antibodies into an even more powerful “tri-specific antibody”.

Dr Gary Nabel, the chief scientific officer at Sanofi and one of the report authors, told the BBC News website: “They are more potent and have greater breadth than any single naturally occurring antibody that’s been discovered.”

The best naturally occurring antibodies will target 90% of HIV strains.

“We’re getting 99% coverage, and getting coverage at very low concentrations of the antibody,” said Dr Nabel.

Experiments on 24 monkeys showed none of those given the tri-specific antibody developed an infection when they were later injected with the virus.

Dr Nabel said: “It was quite an impressive degree of protection.”

The work included scientists at Harvard Medical School, The Scripps Research Institute, and the Massachusetts Institute of Technology.

‘Exciting’

Clinical trials to test the antibody in people will start next year.

Prof Linda-Gail Bekker, the president of the International Aids Society, told the BBC: “This paper reports an exciting breakthrough.

“These super-engineered antibodies seem to go beyond the natural and could have more applications than we have imagined to date.

“It’s early days yet, and as a scientist I look forward to seeing the first trials get off the ground in 2018.

“As a doctor in Africa, I feel the urgency to confirm these findings in humans as soon as possible.”

Dr Anthony Fauci, the director of the US National Institute of Allergy and Infectious Diseases, said it was an intriguing approach.

He added: “Combinations of antibodies that each bind to a distinct site on HIV may best overcome the defences of the virus in the effort to achieve effective antibody-based treatment and prevention.”

Follow James on Twitter.

Article source: http://www.bbc.co.uk/news/health-41351159