A Molecular map of aging

A new genetic database could help reveal why animals age so differently

Even closely related animals can have drastically different life spans, a fact that scientists have been puzzling over for years. Mice, which live about two years, got the short end of the longevity stick: their rodent cousin, the Southern flying squirrel, can live nearly 20 years. Chimps are 99 percent genetically identical to humans but live only half as long. Now a new resource could help pinpoint the genetic changes that underlie those differences.

In a study of mice, researchers at Stanford University and the National Institute on Aging (NIA) have generated a database that catalogues how gene expression--a measure of how active a gene is--changes in different parts of the body as the animals age. The researchers' findings suggest that different tissues age very differently, and this could help pinpoint when it is appropriate to use mice as a model of human aging--and when it's not.