Three parent babies, the gamification of protein, and mapping matter
Chemistry, Biology, Physics: Three scientists talk through big recent developments in their fields.
Physics – Ceri Brenner
On 4 October, the 2016 Nobel Prize in Physics was awarded for the discovery of topology applied to ultra-cold quantum states of matter: a mathematical description that explains why certain materials have quantised levels of conductivity – meaning, the degree to which they conduct electricity – when cooled to only a few degrees above absolute zero. If that leaves you scratching your head, you’re not alone. These theoretical physicists started their investigation as they too found it strange. In doing so they opened the door for the development of innovative materials for the next generation of electronics and quantum computers.
Cooling certain materials down to a few degrees above absolute zero (-273 degrees Celsius) can cause them to enter a superconductive state, since the particles have almost zero motion and allow electricity to flow with no resistance. In 1980 a surprise result was noted – when subjected to a strong magnetic field the conductance of a layer between two semiconductors appeared to increase in integer values only (doubled, tripled, quadrupled . . . you get the idea) as the magnetic field was decreased. In other words, the conductance was quantised. It is now known as the quantum Hall effect, but physics then was unable to explain it.
Enter David Thouless and his topological thinking. Topology is a type of maths that describes which geometric properties of an object remain as it is stretched or deformed. The common analogy is to think of shapes in terms of the number of holes they have. Topologically speaking, a bagel and a teacup belong to the same category, since they both have one hole, and there are no objects with “half a hole”.
Thouless suggested that the electrons moving between the superconducting layers were acting collectively as a topological quantum fluid and therefore their collective measured property, their conductance, would vary in integer steps. Thouless received half of this year’s Nobel prize, while Duncan Haldane and Michael Kosterlitz shared the other half for similar discoveries. Matter’s mysteries revealed through mathematics.
Ceri Brenner is a physicist who works for the Science and Technology Facilities Council
Biology – Lydia Leon
Two billion years ago a bacterial neighbour became engulfed within the cells of our distant ancestors, a chance encounter that began one of the most important relationships in evolutionary history. We are now dependent upon the energetic wizardry of these glucose-hungry visitors, mitochondria. Thousands exist within any one human cell and help convert food into usable forms of energy.
We inherit our mitochondria exclusively from our mothers. Unfortunately, some otherwise healthy women produce eggs with a large number of faulty mitochondria inside them. These eggs, if fertilised, develop into infants with a spectrum of rare disorders. Given their centrality to cellular life, these disorders are often devastating and affect all systems of the body. Most patients do not make it through the first year of life.
Recent developments in IVF technologies have given hope to the nearly 3,000 women in the UK at risk of having a child with mitochondrial disease. The main technique retains the nucleus (DNA containing component) of an a risk mother’s fertilised egg, discards the rest which includes the unhealthy mitochondria, and then transfers this nucleus to a healthy donor’s egg in which the opposite steps have been taken. Because mitochondria carry a very tiny amount of DNA within their membranes, infants born to this technique have been dubbed “three-parent babies”.
In September it was announced that the first baby in the world had been born through this technique. The healthy infant, now five months old, was born to Jordanian parents who had previously had two children with Leigh syndrome, a mitochondrial disorder. Both died in infancy. The procedure was carried out by a US doctor in a Mexican clinic. Little is known about the specifics, and some have raised ethical concerns about the choice of Mexico, as the country has less clear embryology laws than some. Nevertheless, many have heralded this as a major step towards reducing childhood diseases, and improving the opportunities available to parents who are desperate to have a child free from their devastating effects.
Lydia Leon is a PhD student at University College London
Chemistry – Mark Lorch
Computer games can be very addictive. Who hasn’t spent too long tapping away only to feel guilty about their wasted hours crushing candy? Maybe you could do with a change of game. How about something that, in the process of playing, actually helps scientists solve serious questions?
Modern biochemists can collect vast amounts of data about genomes, proteins and biological interactions. Sifting through this information to solve nature’s puzzles is highly time-consuming. Which is why some scientists have turned to the crowd and gamified the data analysis process. The result is apps like Phylo, which turns the process of finding similarities in genomic data into an addictive puzzle, or Eyewire, where players help map neural pathways in the brain. Most successful of all is Foldit, a game where players solve structures of proteins.
Proteins are your body’s molecular machines. They have a role in every function: digesting your food, focusing light entering your eyes, carrying oxygen around your blood, making up the antibodies for your immune system, plus tens of thousands of other functions. Each protein starts life as a long thin chain that then folds into a very specific shape, which it must adopt to function correctly. To understand how a protein works, scientists must attempt to work out each protein’s structure. This is a laborious process. The data that is collected gives a scientist an idea of the protein’s overall shape, but not which bit goes where. They must start with the long chain and try to thread, fold and twist it in such as way that it fits into this overall shape. It is an extremely complicated 3D jigsaw puzzle.
Recently the Foldit team added a feature that gamified that threading process. Then they held a competition, pitting two highly trained professionals, with years of experience solving protein structures, against 469 Foldit players collaborating online from all over the globe. The results, published in Nature Communications, show that the amateur gamers produced structural models at least as good as the trained scientists. Choose your app wisely and you can beat a professor at their own game.
Mark Lorch lectures in chemistry at Hull University