Modern genetics vs. ancient frog-kill...( MOSCOW Idaho Scientists at the Univ...)

MOSCOW, Idaho Scientists at the University of Idaho currently are involved in a CSI-like investigation of a killer known to have been running rampant for the past decade. But the killer's name can't be found on the FBI's Most Wanted list. Instead, it's on the minds of ecologists on every continent in the world.

Its name is Batrachochytrium dendrobatidis (Bd). It is a "chytrid" fungus that lives on keratin, a type of protein found in the skin of amphibians, and is particularly deadly for certain species of frogs. A summary of key findings from the 2004 Global Amphibian Assessment states that 43 percent of all frog species are declining in population, with less than 1 percent showing increases. Although there are many reasons for frog decline, including climate change and habitat loss, Bd seriously is affecting a growing number of species.

"This fungus is really bizarre," said Erica Bree Rosenblum, assistant professor of biological sciences at the University of Idaho and lead author of the study published this week in the Proceedings of the National Academy of Sciences (PNAS). "It's a member of an group of ancient fungi that are at least a half billion years old. But it only recently began killing amphibians and unequivocally is responsible for a lot of the catastrophic frog die-offs during the past decade."

Previous studies have shown that once Bd is introduced to a habitat, up to 50 percent of amphibian species and 80 percent of individuals may die within one year. The fungus has been studied for the past decade, yet scientists still do not know much about how Bd kills its host.

However, Rosenblum's new paper brings scientists one step closer to solving the mystery. The study uses some of the most advanced genetic technology available in an attempt to understand how the fungus works at the most basic level. It identifies several gene families for future study, including one strong candidate that may be a key el
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