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News from the University of Colorado in Boulder.
New CU-Boulder study clarifies diversity, distribution of cutthroat trout in Colorado
Sep 24th
A novel genetic study led by the University of Colorado Boulder has helped to clarify the native diversity and distribution of cutthroat trout in Colorado, including the past and present haunts of the federally endangered greenback cutthroat trout.
The study, led by CU-Boulder postdoctoral researcher Jessica Metcalf, was based largely on DNA samples taken from cutthroat trout specimens preserved in ethanol in several U.S. museums around the country that were collected from around the state as far back as 150 years ago. The new study, in which Metcalf and her colleagues extracted mitochondrial DNA from fish to sequence genes of the individual specimens and compared them with modern-day cutthroat trout strains, produced some startling results.
The biggest surprise, said Metcalf, was that the cutthroat trout native to the South Platte River drainage appears to survive today only in a single population outside of its native range — in a small stream known as Bear Creek that actually is in the nearby Arkansas River drainage. The strain from Bear Creek is thought to have been collected from the South Platte River drainage in the 1880s by an early hotelier who stocked the fish in a pond at the Bear Creek headwaters to help promote an early tourist route up Pikes Peak.
“We thought one way to get to the question of which cutthroat trout strains are native to particular drainages was to go back to historical samples and use their DNA as a baseline of information,” said Metcalf of the chemistry and biochemistry department and a former postdoctoral researcher at the Australian Centre for Ancient DNA. “Our study indicates the descendants of the fish that were stocked into Bear Creek in the late 1800s are the last remaining representatives of the federally protected greenback cutthroat trout.”
A second, key set of data was all of the Colorado cutthroat trout stocking records over the past 150 years, a task spearheaded by study co-author and fish biologist Chris Kennedy of the U.S. Fish and Wildlife Service. Between 1889 and 1925, for example, the study showed that more than 50 million cutthroat trout from the Gunnison and Yampa river basins were stocked in tributaries of all major drainages in the state, jumbling the picture of native cutthroat strains in Colorado through time and space.
Originating from the Pacific Ocean, cutthroat trout are considered one of the most diverse fish species in North America and evolved into 14 recognized subspecies in western U.S. drainages over thousands of years. In Colorado, four lineages of cutthroats were previously identified: the greenback cutthroat, the Colorado River cutthroat, the Rio Grande cutthroat and the extinct yellowfin cutthroat.
The museum specimens used in the study came from the California Academy of Sciences, the Smithsonian Museum of Natural History in Washington, D.C., the Academy of Natural Sciences in Philadelphia and the Harvard University Museum of Comparative Zoology. Colorado cutthroat trout specimens were collected by a number of early naturalists, including Swiss scientist and former Harvard Professor Louis Agassiz and internationally known fish expert and founding Stanford University President David Starr Jordan.
The new study, published online today in Molecular Ecology, follows up on a 2007 study by Metcalf and her team that indicated there were several places on the Front Range where cutthroat populations thought to be greenbacks by fish biologists were actually a strain of cutthroats transplanted from Colorado’s Western Slope in the early 1900s.
Other co-authors on the new study included CU-Boulder Professor Andrew Martin and CU-Boulder graduate students Sierra Stowell, Daniel McDonald and Kyle Keepers; Colorado Parks and Wildlife biologist Kevin Rogers; University of Adelaide scientists Alan Cooper and Jeremy Austin; and Janet Epp of Pisces Molecular LLC of Boulder.
“With the insight afforded by the historical data, we now know with a great deal of certainty what cutthroat trout strains were here in Colorado before greenbacks declined in the early 20th century,” said Martin of CU’s ecology and evolutionary biology department. “And we finally know what a greenback cutthroat trout really is.”
Metcalf and her colleagues first collected multiple samples of tissue and bone from each of the ethanol-pickled trout specimens, obtaining fragments of DNA that were amplified and then pieced together like a high-tech jigsaw puzzle to reveal two genes of the individual specimens. The tests were conducted on two different continents under highly sterile conditions and each DNA sequencing effort was repeated several times for many specimens to ensure accuracy in the study, Metcalf said.
Roughly half of the study was conducted at CU-Boulder and half at the Australian Center for Ancient DNA at the University of Adelaide, where Metcalf had worked for two years. “By conducting repeatable research at two very different, state-of-the-art laboratories, we were able to show the Bear Creek trout was the same strain as the cutthroats originally occupying the South Platte River drainage.”
The Bear Creek trout strain is now being propagated in the Colorado Parks and Wildlife hatchery system and at the USFWS Leadville National Fish Hatchery.
In addition to identifying the Bear Creek cutthroat trout, Metcalf and her colleagues discovered a previously unknown cutthroat strain native to the San Juan Basin in southwestern Colorado that has since gone extinct. The study also confirmed that the yellowfin cutthroat, a subspecies from the Arkansas River headwaters that grew to prodigious size in Twin Lakes near Leadville, also had gone extinct.
Fortunately, most fish preserved by naturalists before 1900 were “fixed” in ethanol, which makes it easier for researchers to obtain reliable DNA than from fish preserved in a formaldehyde solution, a practice that later became popular. Prior to the new study — which included DNA from specimens up to about 150 years old — scientists working in ancient DNA labs had only performed similar research on ethanol-preserved museum vertebrate specimens less than 100 years old.
“One of the exciting things to come from this research project is that it opens up the potential for scientists to sequence the genes of other fish, reptiles and amphibian specimens preserved in ethanol further back in time than ever before to answer ecological questions about past diversity and distribution,” said Metcalf, who conducts her research at CU’s BioFrontiers Institute.
Funding for the study was provided by agencies of the Greenback Cutthroat Trout Recovery Team, including the USFWS, the U.S. Forest Service, the Bureau of Land Management, the National Park Service and Trout Unlimited.
“I think in many cases success depends less on the application of a new technology and more on the convergence of people with shared interest and complementary skills necessary for solving difficult problems,” said Martin. “Our greenback story is really one about what can be discovered when dedicated and talented people collaborate with a shared purpose.”
“We’ve known for some time that the trout in Bear Creek were unique,” said Doug Krieger, senior aquatic biologist for Colorado Parks and Wildlife and the Greenback Cutthroat Trout Recovery Team leader. “But we didn’t realize they were the only surviving greenback population.”
The decline of native cutthroats in Colorado occurred because of a combination of pollution, overfishing and stocking of native and non-native species of trout, said Metcalf. “It’s ironic that stocking nearly drove the greenback cutthroat trout to extinction, and a particularly early stocking event actually saved it from extinction,” she said.
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CU -R U an explanation “foe” or “fiend” when shopping?
Sep 19th
says new CU-Brown University study
The depth of explanation about novel products influences consumer preferences and willingness to pay, according to a study led by the University of Colorado Boulder and Brown University.
When it comes to descriptions about the functions of new and unusual goods — such as a self-watering plant system, special gloves for touchscreens or an eraser for wall scratches — some people prefer minimal details. Dubbed “explanation foes” in the study, they gain a strong sense of understanding and desire for products through shallow explanations.
In contrast, other people — dubbed “explanation fiends” in the study — derive desire for products from deep and detailed explanations.
“There are these two different types of consumers,” said lead author Phil Fernbach, assistant professor of marketing at CU-Boulder’s Leeds School of Business. “On these two sides, consumers differ in the amount of detail that makes them feel like they understand and — because of that feeling of understanding — the amount of detail that will make them prefer a product.”
A paper on the subject was published online today in the Journal of Consumer Research.
Researchers say the study results can help consumers make better decisions.
“We’re not making a value judgment on whether it’s better to be an ‘explanation foe’ or ‘fiend,’ ” said Fernbach. “You don’t have to want to know how stuff works, but make sure that your intuition about whether you understand a product is based on objective information and not just a feeling.”
In one part of the study, participants were given varying explanations of a new tinted food wrapper product. “Explanation foes” highly rated their understanding and preference for the item when they read a simple description of how its “white coloring protects food from light that causes it to spoil, thereby keeping food fresh for longer.”
“Explanation fiends” highly rated their understanding and preference for the food wrapper when they read a more detailed description of how “atoms in the tinting agent oscillate when hit by light waves causing them to absorb the energy and reflect it back rather than reaching food, where it would break the bonds holding amino acids together, thereby keeping food fresh for longer.”
The study also found that “explanation foes,” who are more common, tend to have an inflated sense of understanding about novel products. Their heightened perception disappears and their willingness to pay decreases when they attempt to explain how a product works.
Conversely, “explanation fiends” tend to have a more conservative sense of understanding about novel products. For them, attempting to explain how a product works does not have a negative effect on their sense of understanding and their opinion of the product stays the same or increases, according to the study.
Attitudes toward explanation were predicted by a cognitive reflection test that measures how much people naturally engage in deliberative thinking. Each test question elicits an intuitive but incorrect answer and participants who impulsively respond tend to err. These participants are the “explanation foes” who prefer less explanation.
In contrast, those who inhibit their initial responses to the cognitive reflection test and think more deeply tend to correctly answer. These participants are the “explanation fiends” who prefer more in-depth descriptions.
While the study can help consumers with better decision-making, it also yields advice for marketers.
“Marketers should target these different consumer groups with different types of explanations,” said Steven Sloman, a study co-author and professor of cognitive, linguistic and psychological sciences at Brown University.
Robert St. Louis and Julia Shube also were co-authors of the study. They were undergraduate students at Brown during the research. Unilever, a consumer goods company, supported the study.
CU Law School students and alumni to teach high school students statewide about the Constitution
Sep 13th
Constitution Day is a national event that annually commemorates the Sept. 17, 1787, signing of the United States Constitution.
The students and alumni will visit classrooms in Aurora, Boulder, Carbondale, Colorado Springs, Denver, Glenwood Springs, Grand County, Greeley, Fort Collins, Longmont, Watkins and Wray as part of the Colorado Law School Constitution Day Project, launched in 2011 by the Byron White Center for the Study of American Constitutional Law
“The program was such a success last year that we have expanded it significantly for 2012 and hope to continue that expansion in future years,” said Melissa Hart, associate professor of law and director of the Byron White Center. “We are particularly pleased to be able to visit schools all over the state, and will maintain that priority as we expand.
“Our students and alumni are excited about the opportunity to work with high school students and teachers, and to contribute to the important goal of broadening public constitutional literacy.”
The lesson plan, which was created by law students with the guidance of Hart and several high school civics teachers, begins with a review of the basic structure of the Constitution and then focuses on the text of the Fourth Amendment, which prohibits unreasonable searches and seizures of private property by the government. After reviewing the law, students will be guided through a debate about whether a school’s search of a student’s text messages violated the student’s constitutional rights.
In the first year of the project in 2011, the center sent 60 law students to over 50 high school classrooms to teach a lesson, which was followed by student debates involving a hypothetical situation that applied the First Amendment to a student Facebook posting.