Faculty FindingsNo Bones About It • Heart Health • Saving Our Salmon• A Planet Like Earth?
Swimming off the coasts of Australia and New Zealand, the elephant shark is a living fossil on par with other ocean old-timers like the coelacanth fish. New research by Assistant Professor of Biology Scott Roy and colleagues shows that the shark hasn’t changed its genome substantially in hundreds of millions of years.
The study, published in the Jan. 9 issue of the journal Nature, is the first to look at the whole genome of a cartilaginous fish — a group that includes sharks, rays and skates, all of whom have skeletons of rubbery cartilage rather than bone. The elephant shark genome is relatively small, consisting of slightly fewer than 1 billion “letters” of DNA compared with 3 billion in the human genome. But Roy and the rest of the international team of researchers were able to glean some interesting details from this spare genetic sequence.
For instance, the elephant shark doesn’t have the genes for certain proteins that can convert soft cartilage into hard bone. It also lacks the genes for several key immune system cells that provide carefully targeted defenses against specific diseases. These differences, Roy says, give scientists a glimpse at what the ancestor of living vertebrate animals might have looked like. He also says the new genome provides “a very clear signal” that bony fish are more closely related to other bony animals than they are to cartilaginous swimmers like sharks and skates.
With heart donors in short supply, each year more cardiac patients find themselves on the transplant wait list. In collaboration with German researchers, Professor of Biology Gerdi Weidner’s latest study has unveiled best practices for long-term survival during the wait.
“Depression affects life span in general, but it can be even more damaging to cardiovascular patients,” says Weidner, whose study was published in the Feb. 10 issue of the journal Health Psychology. “Mental–health interventions — interventions aimed at maintaining everyday, non-strenuous exercises — can make a significant impact.”
According to California’s Department of Fish and Wildlife, salmon habitats have been degraded by nearly 90 percent since 1940 due to logging, construction and other disturbances that escalate natural erosion. To help restoration efforts, Professor of Earth & Climate Sciences Leonard Sklar and a team of researchers examined rocky riverbeds where salmon dig their underwater nests.
The team found that a range of middle-sized rocks gave salmon the best chance of being able to move them to make nests. Uniform-sized rocks did not attract spawning salmon.
“We’ve created a tool that restoration managers and practitioners can use to optimize the number of fish born in a given area,” says Sklar. “There’s only so much money allotted for habitat restoration each year. We want those efforts to be as effective as possible.”
Stephen Kane, assistant professor of physics and astronomy, and other researchers with NASA’s Kepler Mission have discovered a new rocky planet that might have liquid water on its surface. The new world, dubbed Kepler-186f, orbits within the “Goldilocks Zone” — just the right distance away from its star so that any water on its surface won’t boil away or freeze into ice. The four-year Kepler Mission was launched in March 2009 to scan the nearby Milky Way for Earth-sized or smaller planets in this habitable zone.
Kepler-186f is one of nearly a thousand planets uncovered by the Kepler space telescope, which detects potential planets as they cross in front of their star and cause a tiny dimming of the star’s brightness. But Kepler-186f is a particularly exciting find because it appears to be just slightly bigger than Earth, according to the scientists’ report in the April 18 issue of the journal, Science.
At this size, Kane says, the planet’s atmosphere is more likely to be rich in carbon dioxide and water vapor just like our own planet. And since liquid water is critical to life on Earth, many astronomers believe the search for extraterrestrial life should focus on worlds where liquid water occurs.
Kane was also part of an international team that in January detected a new giant planet located within the Pisces constellation. The planet is perhaps twice the mass of Jupiter and may be one of several planets lurking in the Pisces star systems.
He discovered his first planet in 2005. “That was extremely exciting,” he says, “but I knew this was a field that would grow and grow, and I did wonder if that feeling would go away. It hasn’t."
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