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12 December 2013 1:00 pm ,
Vol. 342 ,
The iconic 125-year-old Lick Observatory on Mount Hamilton near San Jose, California, is facing the threat of closure...
Recent results from the Curiosity Mars rover have helped scientists formulate a plan for the next phase of its mission...
A new, remarkably powerful drug that cripples the hepatitis C virus (HCV) came to market last week, but it sells for $...
In pretoothbrush populations, gumlines would often be marred by a thick, visible crust of calcium phosphate, food...
Evolutionary biologists have long studied how the Mexican tetra, a drab fish that lives in rivers and creeks but has...
Victorian astronomers spent countless hours laboriously charting the positions of stars in the sky. Such sky mapping,...
In an ambitious project to study 1000 years of sickness and health, researchers are excavating the graveyard of the now...
Stefan Behnisch has won awards for designing science labs and other buildings that are smart, sustainable, and...
- 12 December 2013 1:00 pm , Vol. 342 , #6164
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Florida Panthers Dodge Extinction
23 September 2010 5:23 pm
Fifteen years ago, Florida panthers were in a world of hurt. Only about two dozen of the beleaguered predators roamed in southern Florida, and because of inbreeding they suffered from heart defects, reproductive problems, and other maladies. Scientists calculated that there was a 95% chance that the panthers would die out within 20 years if nothing was done.
Fortunately, something did happen. In 1995, biologists invigorated the panthers with some fresh blood, releasing eight cougars from Texas into south Florida. In the 24 September issue of Science, a comprehensive analysis shows how the genetic reinforcement dramatically improved the health of the panthers. "The key thing that's new is just how striking the increase in [health] was," says biologist Craig Packer of the University of Minnesota, Twin Cities, who wrote a commentary on the findings. But it's also becoming apparent that the panthers aren't out of the woods yet.
By the early 20th century, Florida panthers had been hunted nearly to extinction. By the 1980s, biologists had begun tracking and studying the surviving animals. In 1992, an expert panel of researchers urged that the genetic diversity of the panthers be boosted. After 3 years, the U.S. Department of the Interior brought eight Texas cougars to Florida. (Panthers and cougars are different names for pumas, as are mountain lions in the western United States.)
After the introduction, wildlife managers continued to track the health and numbers of the panthers, the cougars, and their offspring. Stephen O'Brien, a geneticist at the National Cancer Institute's Laboratory of Genomic Diversity in Frederick, Maryland, and colleagues researched the genetic impact.
Some biologists became impatient by the pace of O'Brien's team, however. In 2005, a group led by ecologist Stuart Pimm of Duke University in Durham, North Carolina, collected public data contained in reports from wildlife managers and published an analysis showing that kittens with Texas ancestry were surviving at a rate three times higher than kittens from purebred Florida panthers.
O'Brien's more detailed analysis also shows dramatic improvements. By 2007, the population had risen to about 100. Survival rates were higher for cats with Texas ancestry. Between 2002 and 2004, 21% of the offspring of inbred cats survived, compared with 53% for those with some Texas blood. The prevalence of heart defects in mixed offspring was 8%, half that of purebred Florida panthers. The more genetically diverse animals were also noticeably larger and stronger, O'Brien adds. In all, says conservation biologist Paul Beier of Northern Arizona University in Flagstaff, who was not involved, the paper paints a "dramatic picture of the benefits of genetic restoration."
The panthers' problems are not solved, however. The population is currently only about 130—far lower than the goal of more than 500 needed to maintain a stable, healthy population—and has recently stopped increasing. Moreover, signs of inbreeding are starting to appear again, so the panther population would benefit from additional cougars. "It was only a temporary fix," O'Brien says.