In an amazing achievement akin to adding solar panels to your body, a Northeast sea slug sucks raw materials from algae to provide its lifetime supply of solar-powered energy.
“It’s a remarkable feat because it’s highly unusual for an animal to behave like a plant and survive solely on photosynthesis,” said Debashish Bhattacharya. “The broader implication is in the field of artificial photosynthesis. That is, if we can figure out how the slug maintains stolen, isolated plastids to fix carbon without the plant nucleus, then maybe we can also harness isolated plastids for eternity as green machines to create bioproducts or energy. The existing paradigm is that to make green energy, we need the plant or alga to run the photosynthetic organelle, but the slug shows us that this does not have to be the case.”
The sea slug Elysia chlorotica, a mollusk that can grow to more than 2 inches long, has been found in the intertidal zone between Nova Scotia, Canada, and Martha’s Vineyard, Massachusetts, as well as in Florida. Juvenile sea slugs eat the nontoxic brown alga Vaucheria litorea and become photosynthetic — or solar-powered — after stealing millions of algal plastids, which are like tiny solar panels, and storing them in their gut lining,
Photosynthesis is when algae and plants use sunlight to create chemical energy (sugars) from carbon dioxide and water. The brown alga’s plastids are photosynthetic organelles (like the organs in animals and people) with chlorophyll, a green pigment that absorbs light.
This particular alga is an ideal food source because it does not have walls between adjoining cells in its body and is essentially a long tube loaded with nuclei and plastids, Bhattacharya said. “When the sea slug makes a hole in the outer cell wall, it can suck out the cell contents and gather all of the algal plastids at once,” he said.
Based on studies of other sea slugs, some scientists have argued that they steal and store plastids as food to be digested during hard times, like camels that store fat in their humps, Bhattacharya said. This study showed that’s not the case for solar-powered Elysia chlorotica.
“It has this remarkable ability to steal these algal plastids, stop feeding and survive off the photosynthesis from the algae for the next six to eight months,” he said.
The team of Rutgers and other scientists used RNA sequencing (gene expression) to test their solar energy supply hypothesis. The data show that the slug responds actively to the stolen plastids by protecting them from digestion and turning on animal genes to utilize the algal photosynthetic products. Their findings mirror those found in corals that maintain dinoflagellates (also algae) — as intact cells and not stolen plastids — in symbiotic relationships.
Whereas Elysia chlorotica stores plastids, the algal nuclei that are also sucked in don’t survive, and scientists still don’t know how the sea slug maintains the plastids and photosynthesis for months without the nuclei that are normally needed to control their function, Bhattacharya said.
Concern over the potential imminent eruptions of Earth’s supervolcanoes, like Taupo in New Zealand or Yellowstone in the United States, may be quelled by the results of a new study suggesting that geological signs pointing to a catastrophic eruption would be clear far in advance.
To help forecast supervolcano eruptions, the study led by the University of Illinois has quantified the often-overlooked effects of tectonic stress on the rocks that house these sleeping giants, and suggests that people need not be quick to panic — at least not yet.
In the study, researchers set out to investigate regional-scale tectonic stress and unexpectedly found that their models could help forecast supervolcano eruption timing and inform experts on what to expect, geologically, well before an eruption.
“Traditionally, it is thought that eruptions occur when the pressure caused by hot magma overtakes the strength of a volcano’s roof rock,” said geology professor Patricia Gregg. “But supervolcanoes tend to occur in areas of significant tectonic stress, where plates are moving toward, past or away from each other. That plate motion will affect model calculations.”
The team created a model based on the Taupo Volcanic Zone in northern New Zealand. They chose this system because of its relatively uncomplicated extensional tectonic setting — the type of area often associated with supervolcanoes. However, their models found that any tectonic stress would have a profound effect on the stability of supervolcanoes.
“It does not matter if it is extensional, compressional or shear stress,” Cabaniss said. “Any tectonic stress will help destabilize rock and trigger eruptions, just on slightly different timescales. The remarkable thing we found is that the timing seems to depend not only on tectonic stress, but also on whether magma is being actively supplied to the volcano.”
Using their model, the team looked at scenarios with different amounts of stress, tectonic plate movement and magma supply. They found that in any given tectonic setting, the magma reservoirs inside of supervolcanoes appear to remain stable for hundreds to thousands of years while new magma is being actively suppled to the system.
“We were initially surprised by this very short timeframe of hundreds to thousands of years,” Gregg said. “But it is important to realize that supervolcanes can lay dormant for a very long time, sometimes a million years or more. In other words, they may remain stable, doing almost nothing for 999,000 years, then start a period of rejuvenation leading to a large-scale eruption.”
Of course, panic sets in whenever Yellowstone or Taupo experience any change in seismic or geyser activity, but this research suggests that the precursors to catastrophic eruption will be far greater and long-lasting than anything yet documented, the researchers said.
“When new magma starts to rejuvenate a supervolcano system, we can expect to see massive uplift, faulting and earthquake activity,” Gregg said. “Far greater than the meter-scale events we have seen in recent time. We are talking on the range of tens to hundreds of meters of uplift. Even then, our models predict that the system would inflate for hundreds to thousands of years before we witness catastrophic eruption.”
“People need to keep in mind that sites like Yellowstone are very well-monitored,” Cabaniss said. “It is also important to note that our research suggests that the whole rejuvenation-to-eruption process will take place over several or more human lifetimes. Our models indicate that there should be plenty of warning.”
Taking measures against climate change and converting into societies that use significant amounts of renewable energy for power are two of the most important issues common to developed countries today. One promising technology in those efforts uses hydrogen (H2) as a renewable energy source. Although it is a primary candidate for clean secondary energy, large amounts of H2 must be converted into liquid form, which is a difficult process, for easier storage and transportation. Among the possible forms of liquid H2, ammonia (NH3) is a promising carrier because it has high H2 density, is easily liquefied, and can be produced on a large-scale.
Additionally, NH3 has been drawing attention recently as a carbon-free alternative fuel. NH3 is a combustible gas that can be widely used in thermal power generation and industrial furnaces as an alternative to gasoline and light oil. However, it is difficult to burn (high ignition temperature) and generates harmful nitrogen oxides (NOx) during combustion.
Japan focused on a “catalytic combustion method” to solve the NH3 fuel problems. This method adds substances that promote or suppress chemical reactions during fuel combustion. Recently, they succeeded in developing a new catalyst which improves NH3 combustibility and suppresses the generation of NOx. The novel catalyst (CuOx/3A2S) is a mullite-type crystal structure 3Al2O3·2SiO2 (3A2S) carrying copper oxide (CuOx). When NH3 was burned with this catalyst, researchers found that it stayed highly active in the selective production of N2, meaning that it suppressed NOx formation, and the catalyst itself did not change even at high temperatures. Additionally, they succeeded with in situ (Operando) observations during the CuOx/3A2S reaction, and clarified the NH3 catalytic combustion reaction mechanism.
Since 3A2S is a commercially available material and CuOx can be produced by a method widely used in industry (wet impregnation method), this new catalyst can be manufactured easily and at low cost. Its use allows for the decomposition of NH3 into H2 with the heat from (low ignition temperature) NH3 fuel combustion, and the purification of NH3 through oxidation.
“Our catalyst appears to be a step in the right direction to fight anthropogenic climate change since it does not emit greenhouse gasses like CO2 and should improve the sophistication of renewable energy within our society,” said study leader Dr. Satoshi Hinokuma of IROAST. “We are planning to conduct further research and development under more practical conditions in the future.”
An innovative, eel-like robot developed by engineers and marine biologists at the University of California can swim silently in salt water without an electric motor. Instead, the robot uses artificial muscles filled with water to propel itself. The foot-long robot, which is connected to an electronics board that remains on the surface, is also virtually transparent.
The team, which includes researchers from UC San Diego and UC Berkeley, . Researchers say the bot is an important step toward a future when soft robots can swim in the ocean alongside fish and invertebrates without disturbing or harming them. Today, most underwater vehicles designed to observe marine life are rigid and submarine-like and powered by electric motors with noisy propellers.
“Instead of propellers, our robot uses soft artificial muscles to move like an eel underwater without making any sound,” said Caleb Christianson, a Ph.D. student at the Jacobs School of Engineering at UC San Diego.
One key innovation was using the salt water in which the robot swims to help generate the electrical forces that propel it. The bot is equipped with cables that apply voltage to both the salt water surrounding it and to pouches of water inside of its artificial muscles. The robot’s electronics then deliver negative charges in the water just outside of the robot and positive charges inside of the robot that activate the muscles. The electrical charges cause the muscles to bend, generating the robot’s undulating swimming motion. The charges are located just outside the robot’s surface and carry very little current so they are safe for nearby marine life.
“Our biggest breakthrough was the idea of using the environment as part of our design,” said Michael T. Tolley, the paper’s corresponding author and a professor of mechanical engineering at the Jacobs School at UC San Diego. “There will be more steps to creating an efficient, practical, untethered eel robot, but at this point we have proven that it is possible.”
Previously, other research groups had developed robots with similar technology. But to power these robots, engineers were using materials that need to be held in constant tension inside semi-rigid frames.
“This is in a way the softest robot to be developed for underwater exploration,” Tolley said.
The robot was tested inside salt-water tanks filled with jelly fish, coral and fish at the Birch Aquarium at the Scripps Institution of Oceanography at UC San Diego and in Tolley’s lab.
The conductive chambers inside the robot’s artificial muscles can be loaded with fluorescent dye (as shown in the video accompanying the study and this release). In the future, the fluorescence could be used as a kind of signaling system.
Next steps also include improving the robot’s reliability and its geometry. Researchers need to improve ballast, equipping the robot with weights so that it can dive deeper. For now, engineers have improvised ballast weights with a range of objects, such as magnets. In future work, researchers envision building a head for their eel robot to house a suite of sensors.
Readers might nod along or roll their eyes at a newspaper opinion piece, but a new study provides evidence that op-ed columns are an effective means for changing people’s minds about the issues of the day.
Through two randomized experiments, researchers found that op-ed pieces had large and long-lasting effects on people’s views among both the general public and policy experts. also found that Democrats and Republicans altered their views in the direction of the op-ed piece in roughly equal measure.
The New York Times launched the first modern “opposite of the editorial page,” or op-ed page, on Sept. 21, 1970 to promote discussion and learning about salient issues in the news. Today, op-ed columns appear daily in all major print and online newspapers. Advocacy groups, political organizations, think tanks, and academics invest substantial time and resources into generating op-ed pieces.
“The time and energy it takes to produce an op-ed pieces raises a question: Are people persuaded by op-eds?” said Alexander Coppock, assistant professor of political science at Yale and the study’s lead author. “We found that op-ed pieces have a lasting effect on people’s views regardless of their political affiliation or their initial stance on an issue. People read an argument and were persuaded by it. It’s that simple.”
The researchers enrolled 3,567 people into the study through an online tool. In an initial survey, participants shared background information, such as their gender and party affiliation. They were randomly assigned into a control group or one of five “treatment” groups. Participants in the treatment groups were shown one of five op-eds that had been published in a major news outlet by a writer affiliated with the Cato Institute, a libertarian think tank, or U.S. Senator Rand Paul of Kentucky. Participants in the control group were not given an op-ed to read.
The op-eds, which had appeared in advocated libertarian policy positions on issues such as climate change, federal spending on transportation and infrastructure, and instituting a federal flat tax on income. The researchers gauged participants’ immediate reactions to the op-ed pieces and surveyed them again 10 and 30 days later, comparing their responses to those of participants in the control group.
The researchers performed the same experiment on a group of 2,169 “elites,” including journalists, law professors, policy-focused academics, think tank scholars, bankers, and congressional staffers.
In both experiments, people exposed to op-eds shifted their views to support the argument presented in the piece, with the general public being marginally more persuaded than the elites.
While 50% of people in the control group agreed with the views expressed in a given op-ed, 65%-70% of the people in the treatment groups expressed agreement with the op-eds’ authors immediately after reading the pieces, Coppock said.
“These large differences suggest that people are persuadable on policy issues by substantial amounts,” Coppock said.
The gap between the control and treatment groups closed by about half after 10 days, but remained substantial, Coppock noted. Participants’ views changed little between 10 and 30 days after reading the op-eds, demonstrating a lasting effect, he said.
The researchers concluded that op-eds are a cost effective way to influence people’s views. Based on the cost of producing an op-ed, the number of people likely to read it, and its ability to sway a reader’s opinion, the researchers estimated that an op-ed costs from about 50 cents to $3 per mind changed.
More than 30 years ago, when University of California, Berkeley researchers discovered telomerase — an enzyme that lengthens chromosome ends and prevents them from fraying enough to kill a cell — speculation ran wild about its role in aging and cancer, setting off a full-court press to produce drugs to activate or block the enzyme.
While neither telomerase-based anti-aging drugs, touted as a “fountain of youth,” nor anticancer drugs have yet appeared, the publication today by UC Berkeley scientists of the first detailed picture of the molecular structure of human telomerase should jump-start that effort, allowing more targeted drug screens and intelligent design of new drugs.
“It has been a long time coming. It took a lot of persistence,” said Kathleen Collins, a UC Berkeley professor of molecular and cell biology who has worked on the enzyme for 26 years.
One bottleneck has been obtaining pure samples of this complex molecule, which is composed of an RNA backbone decorated by six types of protein that move around as they add DNA to the ends of chromosomes. Labs around the world have debated whether the enzyme operates singly or as conjoined twins, and how and how many proteins decorate the RNA backbone.
Without consensus on these questions, it has proven difficult to design a drug to target the molecular machine and either destroy telomerase activity — which could stop a cancer that has boosted its telomerase levels — or restart telomerase, perhaps to prime the body for rapid cell division after a bone marrow transplant.
The newly revealed structure still lacks fine detail, but combined with knowledge of the gene sequence of human telomerase, it provides enough information to start thinking about potential targets for drugs, said first author Thi Hoang Duong “Kelly” Nguyen, a Miller Institute postdoctoral fellow at UC Berkeley.
“The best previous images of human telomerase had a resolution of only 30 Ångstroms; we were able to get about 7 to 8 Ångstroms resolution using cryoelectron microscopy,” Kelly said. “When I got to the point where I could see all the subunits — we had 11 protein subunits in total — it was a moment of, ‘Wow, wow, this is how they all fit together.'”
Nguyen, Collins and Nogales are actively working to improve the resolution to 3 or 4 Ångstroms — about the size of two carbon atoms — which is sufficient for drug design.
Telomerase tops up the telomeres
Telomeres were first detected at a molecular level in the late 1970s by Elizabeth Blackburn, then at UC Berkeley and now president emerita of the Salk Institute for Biological Studies in La Jolla, California. Working with the ciliated protozoan Tetrahymena, she and colleagues showed that the ends of the chromosomes are capped by repeating sequences of DNA. Armed with knowledge of telomere sequence, researchers then showed that telomeres in tissues of multicellular organisms grow shorter each time a cell divides. The telomeres protect the DNA strands from fraying and getting damaged at their ends, much like the plastic tip on the end of a shoelace. The fact that they drop off with each cell division is thought to protect us from cancer, when a cell is hijacked and proliferates continually.
In 1985 at UC Berkeley, Blackburn and then-graduate student Carol Greider discovered telomerase, an enzyme that adds DNA back to the ends of chromosomes, lengthening them and extending the lifespan of the cell. Blackburn, Greider and another colleague, Jack Szosak, shared the 2009 Nobel Prize in Physiology or Medicine for the discovery of telomerase.
Scientists have since found that, in humans and other multicellular organisms, telomerase is expressed only in the embryo, not in most adult cells. That means that most cells at birth have a predetermined ability to grow and divide, after which they die. Many scientists believe that depleted telomeres are a major cause of aging.
Collins has been trying to determine the structure of telomerase ever since the first human telomerase protein was discovered in 1997, and she and her colleagues have discovered and extensively characterized many of the proteins in the large enzyme, as well as the broken-up hairpin structure of the RNA backbone of telomerase. Yet how they all fit together was an enigma because of conflicting results from many different labs.
Nguyen was able to isolate the active enzyme and purify it much better than anyone had before, and employed a new, state-of-the-art cryoelectron microscope to determine the structure of the active telomerase unambiguously. Cryo-EM is a technique for determining molecular structures of compounds that cannot be crystallized and imaged with X-rays, and its developers won the 2017 Nobel Prize in Chemistry.
Once the UC Berkeley team had the structure, Nguyen said, it became clear why genetic mutations in some of the proteins in telomerase interfere with the enzyme to cause disease. In 1999, Collins discovered the first known human disease caused by a telomerase mutation: a mutation in a telomerase protein called dyskerin that is responsible for a rare disease called dyskeratosis congenita. Patients develop anemia as well as skin and gut problems, and most frequently die from bone marrow failure.
The reason, Collins says, is that there are two dyskerin molecules bound to the RNA backbone that have to not only reach out to the network of other proteins but also touch one another, and disease-causing mutations prevent these linkages, crippling the ability of the RNA backbone to survive in cells. Some children with dyskeratosis congenita have telomerase levels about 25 percent of normal and a lifespan of less than two decades. Those with half the normal level of telomerase typically reach a health crisis in mid-life.
Collins is ecstatic to finally have a definitive structure for telomerase and looks forward to learning more about the intricate assembly process of one of the most complex enzymes in the body: a polymerase as complicated as the ribosome, which reads RNA to produce proteins.
“I didn’t think it would be this complicated when I decided to study this molecule,” she said. “I became curious about how telomerase works in 1991, when I was just finishing as a grad student, and I was looking for a really simple polymerase system in which to understand nucleic acid interactions. And I thought, my god you can’t be simpler than this. That was super naive.”
More people have died or been injured in mass school shootings in the US in the past 18 years than in the entire 20th century. researchers have reviewed the history of mass school shootings in the US and found some alarming trends. Lead author Antonis Katsiyannis of Clemson University in the US, together with his colleagues, found the recent killing of 17 people at Marjory Stoneman Douglas High School in Florida is not an isolated occurrence, but part of a deadly epidemic that needs to be addressed.
A shooting is defined as a “mass shooting” when four or more people are killed (excluding the shooter). Sporadic school shootings have occurred at various points in the history of the US. For example, in 1940 a junior high school principal killed six adults including the school’s district business manager. No similar mass shootings occurred in the 1950s and 1960s. However, school shootings have been steadily increasing since 1979. Overall, the death toll from mass school shootings was 12 in the 1980s and 36 in the 1990s.
During the 20th century, mass school shootings killed 55 people and injured 260 others at schools especially in America’s Western region. Most of the 25 shooters involved were white males who acted alone, and only nine were diagnosed as suffering from mental illnesses at the time. Sixty percent of shooters were between 11 and 18 years old.
Since the start of the 21st century there have already been 13 incidents involving lone shooters; they have killed 66 people and injured 81 others.
“In less than 18 years, we have already seen more deaths related to school shootings than in the whole 20th century. One alarming trend is that the overwhelming majority of 21st-century shooters were adolescents, suggesting that it is now easier for them to access guns, and that they more frequently suffer from mental health issues or limited conflict resolution skills,” says Katsiyannis.
The authors explain that such violence can be mitigated through deliberate and sensible policy and legislative actions. These include expanded background checks of potential gun owners, and a ban on assault weapons. Mental health issues among adolescent students and adults should also be addressed more thoroughly. School personnel should also implement tiered models of support and school-based mental health services to support students’ social, emotional, and behavioral well-being and prevent school violence.
“Preventative efforts not only require policy and legislative action but increased and targeted funding across federal, state, local and private sectors,” adds Katsiyannis.
Dog and human gut microbiomes have more similar genes and responses to diet than we previously thought.
Dr Luis Pedro Coelho and colleagues from the European Molecular Biology Laboratory, in collaboration with Nestlé Research, evaluated the gut microbiome of two dog breeds and found that the gene content of the dogs microbiome showed many similarities to the human gut microbiome, and was more similar to humans than the microbiome of pigs or mice.
Dr Luis Pedro Coelho, corresponding author of the study, commented: “We found many similarities between the gene content of the human and dog gut microbiomes. The results of this comparison suggest that we are more similar to man’s best friend than we originally thought.”
The researchers found that changes in the amount of protein and carbohydrates in the diet had a similar effect on the microbiota of dogs and humans, independent of the dog’s breed or sex. The microbiomes of overweight or obese dogs were found to be more responsive to a high protein diet compared to microbiomes of lean dogs; this is consistent with the idea that healthy microbiomes are more resilient.
Dr Luis Pedro Coelho, commented: “These findings suggest that dogs could be a better model for nutrition studies than pigs or mice and we could potentially use data from dogs to study the impact of diet on gut microbiota in humans, and humans could be a good model to study the nutrition of dogs.
“Many people who have pets consider them as part of the family and like humans, dogs have a growing obesity problem. Therefore, it is important to study the implications of different diets.”
The researchers investigated how diet interacted with the dog gut microbiome with a randomized controlled trial using a sample of 64 dogs, half of which were beagles and half were retrievers, with equal numbers of lean and overweight dogs. The dogs were all fed the same base diet of commercially available dog food for four weeks then they were randomized into two groups; one group consumed a high protein, low carb diet and the other group consumed a high carb, low protein diet for four weeks. A total of 129 dog stool samples were collected at four and eight weeks. The researchers then extracted DNA from these samples to create the dog gut microbiome gene catalogue containing 1,247,405 genes. The dog gut gene catalogue was compared to existing gut microbiome gene catalogues from humans, mice and pigs to assess the similarities in gene content and how the gut microbiome responds to changes in diet.
Researchers at Carnegie Mellon University have used an inexpensive 3-D printer to produce flat plastic items that, when heated, fold themselves into predetermined shapes, such as a rose, a boat or even a bunny.
Lining Yao, assistant professor in the Human-Computer Interaction Institute and director of the Morphing Matter Lab, said these self-folding plastic objects represent a first step toward products such as flat-pack furniture that assume their final shapes with the help of a heat gun. Emergency shelters also might be shipped flat and fold into shape under the warmth of the sun.
Self-folding materials are quicker and cheaper to produce than solid 3-D objects, making it possible to replace noncritical parts or produce prototypes using structures that approximate the solid objects. Molds for boat hulls and other fiberglass products might be inexpensively produced using these materials.
Yao will present her group’s research on this method, which she calls Thermorph, at CHI 2018, the Conference on Human Factors in Computing Systems.
Other researchers have explored self-folding materials, but typically have used exotic materials or depended on sophisticated processing techniques not widely available. Yao and her research team were able to create self-folding structure by using the least expensive type of 3-D printer — an FDM printer — and by taking advantage of warpage, a common problem with these printers.
“We wanted to see how self-assembly could be made more democratic — accessible to many users.”
FDM printers work by laying down a continuous filament of melted thermoplastic. These materials contain residual stress and, as the material cools and the stress is relieved, the thermoplastic tends to contract. This can result in warped edges and surfaces.
“People hate warpage,” Yao said. “But we’ve taken this disadvantage and turned it to our advantage.”
To create self-folding objects, she and her team precisely control this process by varying the speed at which thermoplastic material is deposited and by combining warp-prone materials with rubber-like materials that resist contracture.
The objects emerge from the 3-D printer as flat, hard plastic. When the plastic is placed in water hot enough to turn it soft and rubbery — but not hot enough to melt it — the folding process is triggered.
Though they used a 3-D printer with standard hardware, the researchers replaced the machine’s open source software with their own code that automatically calculates the print speed and patterns necessary to achieve particular folding angles.
“The software is based on new curve-folding theory representing banding motions of curved area. The software based on this theory can compile any arbitrary 3-D mesh shape to an associated thermoplastic sheet in a few seconds without human intervention.”
“It’s hard to imagine this being done manually.”
Though these early examples are at a desktop scale, making larger self-folding objects appears feasible.
“We believe the general algorithm and existing material systems should enable us to eventually make large, strong self-folding objects, such as chairs, boats or even satellites.”
When organisms change during the course of evolution, often what drives new forms is not genes themselves, but gene regulation — what turns genes on and off. A new study identifies the kind of gene regulation most likely to generate evolutionary change.
Most modern organisms store genetic information in DNA and transcribe the information from DNA into RNA. Protein “transcription factors” that inhibit or enhance transcription of genes in the DNA are said to regulate gene expression.
“That really surprised us,” said senior author Andreas Wagner, an external professor at the Santa Fe Institute and chairman of the Institute of Evolutionary Biology and Environmental Studies at the University of Zürich. “It’s not self-evident. It’s one of those things you just don’t know before you look.”
“New forms of regulation are crucial for a lot of new features of life,” said Wagner. “What distinguishes the body plan of humans from that of sea urchins or fruit flies is new kinds of regulation — turning the right genes on and off at the right time.”
Previous work by the same team showed that transcription factors show high levels of two key evolutionary traits — robustness and evolvability. A robust system functions relatively normally even when mutations occur. In contrast, an evolvable system is able to generate new forms or traits in response to new mutations.
Added lead author Joshua Payne (ETH Zurich, Swiss Institute of Bioinformatics): “We find that transcription factor binding sites are highly evolvable because mutations often create binding sites for other transcription factors. In this way, mutations to transcription factor binding sites can readily bring forth phenotypic variation.”
The evolvability of transcriptional regulation may help explain why organisms switched from using RNA to store information some 4 billion years ago, to using DNA and proteins, Wagner said.