PROVIDENCE, R.I. [Brown University] For years, researchers have been investigating how mutations of a gene called Indy (for "I'm Not Dead Yet") affect metabolism, life span, and reproductive fitness in both mammals and fruit flies. So far mutations in Indy have been studied experimentally only in the lab. No longer. A new study reports that a particularly important variation of the gene with much the same life-governing consequences has actually been widespread among fruit flies, judging by lines gathered from the wild across the entire globe for 60 years.
The naturally occurring variation is the insertion of a transposable element an invasive snippet of DNA at a specific position on Indy. Researchers, including Brown University biology professors Stephen Helfand and Robert Reenan, found that the transposable element, called Hoppel, was present to varying extents in 17 of 22 fruit fly lines gathered from all over the world as far back as the middle of last century. Hoppel was present in 100 percent of a captive fly line started in 2006 in Mumbai, India, for example, and 55 percent of flies descended from those gathered in Oahu, Hawaii, in 1955.
Helfand recalled that in 2000 when he first published a paper in Science demonstrating the effect of Indy on life span, a couple of reporters asked him why a mutation that conveyed such advantages wasn't found in the wild.
Indeed, 14 years later the prevalence of Hoppel insertion suggests that it has been beneficial to flies in the wild and therefore persisted during their evolution, said Helfand, of Brown's Department of Molecular Biology, Cellular Biology, and Biochemistry.
"It's kind of remarkable that just the Hoppel in Indy should affect fertility and life span because these flies from around the world are from such differing genetic backgrounds," said Helfand. "This suggests that we are correct that Indy does play a role in longevity. If it does it in the lab, tha
|Contact: David Orenstein|