College of Charleston professors are always doing interesting research, which can lead to news-making discoveries like the three below about genetic mutations, “UFOs” and solar flares.
Discovery: Not-So-Random Genetic Mutations
It’s long been thought that genetic mutations were random, with most of the parts of DNA being equally likely to experience copying errors as cells divide. But biology professor Matt Rutter and his research partners at the University of California, Davis; South Dakota State University; and the Max Planck Institute for Developmental Biology in Germany have discovered that isn’t the case, at least when it comes to a small flowering weed called thale cress (or Arabidopsis thaliana to biologists).
They found a distinct pattern where many genes, particularly genes crucial to plant function, experience very low rates of mutation while other parts of DNA experience a higher rate. They also discovered a signature of chemical modifications of the DNA molecule at these low mutation regions that could be a mechanism to guide the error-correcting proteins that can prevent mutation.
“Our findings suggest a much more dynamic contribution of mutation to evolution – with some parts of the genome free to change quickly while others are kept in a protected state,” says Rutter. “We don’t know yet if these processes are present widely in plants or in other organisms like animals! We’ve had quite a bit of attention to our paper. It is a bit controversial, so I expect there will be a lively debate around our findings for years to come.”
That’s fitting, given that Rutter has been working on this project for 18 years, starting when he was a postdoctoral researcher at the University of Maryland. While the plant grows quickly, it takes many years to produce all the generations of growth necessary to observe a relatively rare phenomenon like mutation in detail.
“I am incredibly excited and proud to see our findings come out,” says Rutter. “While there are still more questions, I think we have a much clearer understanding about the puzzle we started out looking at – there are fewer negative effects than expected from mutation because the critical parts of the genome are protected.”
Discovery: Tsunami-Like Shock Waves Propagating Through Galaxies
George Chartas, associate professor of astronomy and physics, has a thing for UFOs, but not the type you’re thinking about. His UFOs are ultrafast outflows: powerful winds of ionized gas that are driven by black holes to speeds approaching the speed of light.
Explaining that most galaxies harbor supermassive black holes in their centers, Chartas says, “These powerful winds are thought to regulate the evolution of the host galaxy by either removing the gas from the galaxy or heating it up and thus quenching star formation.”
Basically, black holes have hissy fits – and Chartas and his research partners at Clemson University and the University of Chicago were finally able to detect the resulting gamma rays to show that ultrafast winds are responsible for regulating the growth of galaxies. To make a convincing case, they selected two samples of galaxies for their study – ones that did not contain ultrafast outflows and those that did using NASA’s Fermi Gamma-ray Space Telescope. Only those galaxies with ultrafast winds had detectable gamma rays, while the intensity of the gamma-ray emission was also stronger in galaxies that had the most powerful winds. They published their findings in The Astrophysical Journal last October, with Clemson reporting on it, as well.
“The discovery of gamma rays from galaxies that have UFOs is important because it shows that the powerful ultrafast winds produced by the supermassive black holes in the centers of galaxies can transfer a significant amount of energy to their host galaxies and eventually disable star formation,” says Chartas. “This discovery can also help us understand what happened in our own Milky Way galaxy.”
Discovery: Largest Known Flare Energy on Extreme Superflare Star
Another star burning bright in the Department of Physics and Astronomy is Ashley Pagnotta. During her graduate work at Louisiana State University (LSU) in 2009, she was looking at a photo from 1900 of the constellation Ophiuchus when she discovered a prior eruption or nova of a binary star system called V2487 Oph (the other was in 1998).
Flash forward to 2015, when she and her LSU colleague Brad Schaefer used the Kepler satellite telescope to stare at V2487 Oph for some two months straight to figure out what the orbital period was for the two stars.
“It took us a bit to get to actually looking at the data because we are slow and easily distractible,” says the assistant professor with a laugh. “We finally got around to it this past summer with the help of one my students, [senior astrophysics major] Seth Zoppelt – but, instead of finding some nice regular variations indicative of an orbital period, we found giant superflares. We were very excited to make the discovery because it was completely unexpected!”
The results of their discovery were published here.
Astronomers have known about flares – which happen when the magnetic field lines get all twisted up, snap and fling a bunch of hot charged particles into space – for some time, as they occur on single stars like our Sun. But superflares are much more energetic. And no one has ever discovered them before on a recurrent nova.
“They happen approximately every 1.2 days and, at their strongest, are apparently more energetic than any superflares we’ve seen before,” says Pagnotta. “We’re lucky that our Sun will never put out any superflares, because its regular flares are potentially dangerous enough if they’re aimed at Earth. Superflares, being much more powerful, would be extremely bad for life on any planet orbiting a star that produces them. They basically would strip the atmosphere and make the surface really inhospitable to life.”
And that is a discovery no one wants to make.