From graduate school to a career as an assistant professor in the USC Leonard Davis School of Gerontology and the USC College of Letters, Arts and Sciences, Longo's ideas were questioned by peers and students alike as he explored a new way to look at aging that directly opposes principles set forth by Darwin in his theory of natural selection.

It has long been accepted that natural selection happens on the individual level the better suited an organism is to its environment, the more likely it is to reproduce, forcing the species to change, or evolve, over time.

Longo's theory, in contrast, hinges on a process called "group selection," believed by most scientists to be wrong because it proposes that selection happens at the group level rather than the individual .

The gerontologist also rejects the commonly accepted theory that aging happens by chance and that, like a car, an organism runs well until it starts to breaks down and eventually just stops working. In research published in the Sept. 27 edition of the Journal of Cell Biology, Longo proposes that aging is programmed so that the majority of a population dies prematurely to provide nutrients for the sake of a few individuals who have acquired the genetic mutations that increase their chances of reproduction.

The research is based on observations of programmed aging in baker's yeast by Longo and co-author Paola Fabrizio. Scientists use baker's yeast to study aging because the molecular pathway that regulates its longevity is similar to that in other organisms, such as mice and possibly humans, Longo said.

"Basically, it is the first demonstration, to our knowledge, that aging is programmed and altruistic," Longo said.

"The organisms we have studied die long b
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Contact: Usha Sutliff
sutliff@usc.edu
213-740-0252
University of Southern California
27-Sep-2004