Designer babies, leap seconds, and the protein database
Chemistry, Biology, Physics: Three scientists talk through recent developments in their fields.
This article is a preview from the Spring 2015 edition of New Humanist. You can find out more and subscribe here.
Chemistry - Mark Lorch
Mention protein and most people think of a dietary staple to go with carbohydrates and fats. But to a biochemist they are nature’s robots, tiny and more exquisitely constructed than any manmade machinery. Proteins are the machines and scaffolding that govern just about every chemical process in living things. From structures that replicate DNA to the antibodies that fight infections and the collagen that forms your ligament: all are proteins. And just as a manmade machine designed to, say, wash your dishes has a different structure from one that toasts your bread, so it is with proteins. Each type has its own unique shape.
Figuring out the structures of proteins is the province of structural biologists. Why bother working out what proteins look like? Simply because if we know the shape of a protein we can also get insights into how it functions.Viruses are a particularly interesting subject because they are almost entirely made of protein capsules designed to invade and deliver their genetic material into cells, turning the host cell into a zombie that replicates more viruses.
A group from the famous Centers for Disease Control in Atlanta, USA have been investigating proteins from influenza. They want to know if an outbreak of deadly flu in seals poses a risk to humans. The worry is that since the strain of flu has already crossed from birds to seals, it could jump to humans. The team investigated two proteins: haemagglutinin, responsible for the virus latching onto and fusing with host cells, and neuraminidase, which allows the cell laden with newly formed viruses to burst open and spread new infectious particles. They compared their findings to other structures and found that the seal flu proteins still prefer to bind to bird cells. They suggest that more mutations, leading to small changes in the protein structure of this strain of flu, would be needed before it would infect humans. Should this happen the present flu vaccines probably wouldn’t protect against this variant of flu. This sort of research rarely makes the headlines, but without such work we’d have no information to deal with future disease outbreaks.
Mark Lorch lectures in chemistry at Hull University
Physics - Rory Fenton
Scientists have a problem: their clocks are too accurate. So accurate, in fact, that this year will have to be one second longer than usual to make up for it. This “leap second” is the result of changes in how we define the second.
Once known as one 86,400th of the time the Earth takes to rotate once on its own axis (or, well, a “day”), the second is now pegged to the radioactivity of caesium. It is on these precise “atomic clocks” that the world’s computers, satellites and financial services are now run.
This presents a problem: measured with these new clocks, the length of each day is not constant. Rather like a spinning ballerina slowing down by moving her arms out, the tides of the ocean, earthquakes and movements in the Earth’s core cause the planet, on average, to slow down, meaning that each day is slightly shorter than the last. The daily change is tiny but if left unchecked in two millennia, our clocks will be ahead of the Earth by about four hours, so noon would strike at 4pm.
To prevent this rather confusing outcome, physicists agreed to add an extra second to atomic clocks every few years to keep the two roughly in time. Unlike the leap year, the leap second follows no regular pattern, because of the unpredictable nature of the natural forces behind it. This January, the International Earth Rotation and Reference Systems Service announced that 2015 will see a leap second on 30 June, making clocks strike 11:59:60, and then midnight.
This can cause problems for computers. Following the last leap second in 2012, websites such as Reddit and LinkedIn went down, as servers were thrown by the sudden change in the length of a day. Qantas, the Australian airline, saw 300 flights delayed as its computer system failed. More worryingly, any GPS systems that do not adjust correctly could send drivers off track by several metres.
Alternatively, programmers could follow the lead of Google, who have decided to just let their servers run ever so slightly slower than usual so that the extra second is naturally added by June.
Rory Fenton studied theoretical physics at Imperial College
Biology - Lydia Leon
Genetic research has long captured the imagination of science-fiction writers. The reality is generally less exciting. The most powerful new tool in genetic research is a mysterious element of the bacterial immune system. Known as CRISPR, it helps bacteria ward off infecting viruses by shredding their genetic material. As is often the way in biology, a discovery in one group of organisms inspires research in evolutionarily distinct species. These developments take us into the territory of science fiction.
The CRISPR system works through a “genetic sat-nav” that directs cellular machinery to a specific sequence of DNA, both strands of which are then cut by a DNA “scissor” (a nuclease). In bacteria, this DNA strand break tells other proteins to discard the dangerous viral material. Scientists have developed ways to use the locating and cutting device of CRISPR for genetic engineering – either cutting out unwanted DNA or inserting new code. It is more precise, quick and versatile than other ways of doing this.
The targeted editing of genetic material is less HG Wells, more standard research practice than media coverage suggests. But the exceptional success of CRISPR has renewed the debate about genetic engineering in humans.
One study used CRISPR to edit the genes of mice at the earliest stages of fertilisation. This produced healthy mice pups with a specifically designed genetic change in every cell in their bodies. Previous technologies would only change DNA in a subset of cells within an animal, or rely on lengthy animal-breeding experiments. The scientist behind the experiment told the BBC that we must begin a public debate about our power to edit the human genome at the point of conception. These developments in genetic engineering are making the morally dubious prospect of “designer babies” a real possibility. The main use of CRISPR has been investigating how genetic changes implicate disease risk. But will we ever use such technologies in human reproduction? It’s possible. And it’s a debate we must all take part in, given the huge implications for society and our very concept of self.
Lydia Leon is a PhD student at University College London