Physiology
Winner: Svante Pӓӓbo
Svante Pӓӓbo revealed when he first heard he had been awarded the Nobel Prize in Physiology he thought it was “an elaborate prank on [his] research group,” he said in a press conference. Far from an elaborate prank, the Nobel Assembly awarded Pӓӓbo with the Nobel Prize in Physiology or Medicine for “his discoveries concerning the genomes of extinct hominins and human evolution”
Pӓӓbo is a pioneer in the field of ancient DNA, and his methods advanced the field exponentially. In his work, Pӓӓbo overcame the challenges of extracting DNA from prehistoric bones. Over time, DNA becomes chemically modified and degrades into short segments, leaving only trace amounts of DNA which have been contaminated with bacteria and DNA from contemporary humans.
In 1997, Pӓӓbo became the first person to successfully retrieve and sequence ancient DNA from Neanderthals. Pӓӓbo relied on mitochondrial DNA, which is preserved in larger amounts than other types of DNA, from over 50,000 year old bones. His team continued to work with Neanderthal DNA, culminating in being able to sequence the entire genome. This research led to the discovery that Neanderthals and anatomically modern humans interbred more than 100,000 years ago, and that individuals in Europe and Asia today derive between one and four percent of their ancestry from Neanderthals.
Not only were Pӓӓbo and his team able to derive a genome of a known hominid, but they were able to discover a previously unknown human population from a fragment of a finger bone. This ancestral population, now known as Denisovans, were the first hominid species to be classified by genes alone, instead of fossils.
“Svante’s insights … inspired a generation of scientists and established paleogenomics as a rigorous field of research,” evolutionary biologist Beth Shapiro said in an interview with Science. “Svante brought together teams of scientists who, thanks to his leadership, tenacity, and rigor, established a field that has since allowed unexpected insights into human evolutions, paleontology, ecology, and so many other disciplines.”
Chemistry
Winners: Carolyn R. Bertozzi, Morten Meldal and K. Barry Sharpless
Chemistry is complicated. Building complex molecules is difficult, time consuming and expensive. The winners of this year's Nobel Prize in Chemistry, however, developed a way to construct complex molecules easily, by snapping them together like legos.
Chemists Carolyn Bertozzi from Stanford University, Morten Meldal from the University of Copenhagen and Barry Sharpless of the Scripps Research institute will evenly split this year's Nobel Prize in Chemistry for their development of click chemistry and bioorthogonal chemistry.
Sharpless coined the concept of click chemistry about 20 years ago, identifying it as a simple and reliable form of chemistry, involving quick reactions and avoiding unwanted byproducts. Molecules could, essentially, click together like lego bricks, making them easier to work with.
Independently of each other, Sharpless and Meldal developed a way of easily snapping small azide and alkyne molecules together into a multipart ring using a copper catalyst. Meldal found the copper is what controlled this reaction, whereas Sharpless demonstrated it is essentially a loaded spring released by the copper, allowing it to jump forward and snap into the alkyne. This reaction, the copper catalyzed azide-alkyne cycloaddition, is the crown jewel of click chemistry. It is utilized in pharmaceutical development, DNA and mapping.
Copper, however, is toxic in living cells and will disrupt biological processes. Click molecules could not be used inside living cells until Bertozzi developed bioorthogonal chemistry. By changing the shape of the alkyne, Bertozzi was able to attach fluorescent substances to the surface of cells, allowing researchers to explore cells and track biological processes.
Bertozzi, Meldal and Sharpless will share the prize of over $900,000 equally. This is Sharpless’ second Nobel prize, and Bertozzi will be the eighth woman to receive a Nobel Prize in Chemistry.
Physics
Winners: Alain Aspect, John F. Clauser and Anton Zeilinger
In the super tiny, subatomic realm of our universe, physics gets weird. Phenomena that violate every known intuition of our macroscopic understanding seem to be the norm in the quantum world. It’s no surprise then that this year’s Nobel prize in physics was connected to one of the strangest of these phenomena: quantum entanglement.
In recognition of their groundbreaking series of experiments on quantum entanglement, physicists Alain Aspect, John F. Clauser and Anton Zeilinger were announced as the winners of this year’s esteemed physics award.
Since its conceptualization in the late 1930s by Albert Einstein, Boris Podolsky and Nathan Rosen, quantum entanglement has been enveloped in controversy. Consisting of two non-interacting particles inexplicably having linked quantum states, quantum entanglement was almost too strange to be true. As a result, many scientists argued there must be a set of hidden variables involved in connecting the two particles.
It wasn’t until the 1960s when physicist John S. Bell mathematically debunked the idea of hidden variables through a series of inequalities. Ten years later, Clauser, a postdoc at the University of California-Berkeley, used these inequalities to develop the first of this year’s Nobel prize-winning experiments.
Clauser created an instrument that would collide two entangled photons at a central polarization filter. The particles would then either stop or continue to a detector. If the hidden variable theory were to be valid, Clauser’s instrument would only make detections that could statistically be chalked up as mere random chance. Surprisingly, the data Clauser produced seemed to indicate quantum entanglement was anything but a coincidence.
This was exciting first evidence for quantum entanglement, however, issues persisted. Fixing these problems, later coined as “loopholes,” became the focus of Aspect and his team in the 1980s.
One of the biggest loopholes lies with the possibility that hidden variables could be introduced by the instrument itself. To fix this, Aspect improved Clauser’s original design by upgrading its various components. With this new device, Aspect was able to change the settings on the emitter while the photons were mid-flight. This eliminated the possibility of the instrument introducing any hidden variables — effectively closing the loophole.
Zeilinger was able to use the work of Clauser and Aspect to demonstrate a fascinating characteristic of entanglement called quantum teleportation. This teleportation allows for information to be spontaneously transmitted between two entangled particles at arbitrary distances. Commercially, this could lead to the development of a super-secure quantum communication network.
Aspect, Clauser and Zeilinger will each receive a third of the prize money.
