Science Notes ; Conservation, Genetics

>Alliance lists species, sites in need of preservation

An alliance of conservation groups has identified nearly 600 sites that, if safeguarded properly, could stave off the extinction of hundreds of species.

The study, released by the Alliance for Zero Extinction, noted that a third of the sites it had located have legal protection, and most are surrounded by dense human populations. The United States ranked among the top 10 countries with the most critical habitat at stake, with sites ranging from a West Virginia cave to a Mississippi pond.

“Although saving sites and species is vitally important in itself, this is about much more,” said Mike Parr, the alliance’s secretary. “At stake are the future genetic diversity of Earth’s ecosystems, the global ecotourism economy worth billions of dollars per year, and the incalculable benefit of clean water from hundreds of key watersheds. This is a one-shot deal for the human race.”

Nearly 800 mammals, birds, amphibians, reptiles and conifers are in danger of extinction, according to the coalition of 52 conservation organizations, including the Bloody Bay poison frog, the whooping crane, the volcano rabbit and the Sulu bleeding-heart dove.

— Washington Post

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>Gene makes hungry mice become more active

When yeast, fruit flies and mice get too little food, they tend to live longer. Scientists trying to understand why know that in yeast and fruit flies, at least, a gene called “silent information regulator 2″ is involved in this unusual effect.

Researchers at the Massachusetts Institute of Technology have figured out what the mouse version of this gene does. It makes hungry animals more active.

Danica Chen and Leonard Guarente of MIT’s biology department created “knockout” mice that lacked the Sirt1 gene. The researchers then measured the daily food intake of the “knockout” mice and a group of normal mice when both were allowed to eat as much as they wanted. Then they reduced their daily feed to only 60 percent of their previous intake and measured the amount of activity in their calorie-restricted mice.

When mammals are on a calorie-restricted diet, they typically increase their activity and foraging behavior. And in fact, the normal animals — the ones that still had the Sirt1 gene — greatly increased their activity during nine hungry months at MIT. But the mice lacking the gene either showed no increase in activity or, in many cases, a noticeable decrease.

The researchers also tested the animals’ capacity to stay on a treadmill. The knockout mice actually did better than the normal ones — evidence that lack of Sirt1 hadn’t physically disabled them.

The scientists concluded that Sirt1 is involved in turning up an animal’s “activity dial” when food gets scarce, a pattern that, in nature, might help it find more to eat. Whether the gene is also involved in determining life span remains to be discovered. The research appeared in the journal Science.

— Washington Post