Oct. 1, 2009 -- Scientists have discovered a gene that may affect longevity and leanness.

That gene is called S6K1. In lab tests, the typical life span of mice lacking the S6K1 gene was 9% longer and the maximum life span was 10% longer than mice with that gene intact.

Knocking out the S6K1 gene only affected longevity in female mice; the reasons for that aren't clear from the study, which appears in the Oct. 2 edition of Science.

Female mice without the S6K1 gene also were leaner than female mice that have that gene, regardless of how much they ate, note the researchers, who included Colin Selman, PhD, of the University of Aberdeen in Scotland. Selman worked on the study while at University College London.

Selman's team also notes that mice lacking the S6K1 gene were "smaller than their littermates throughout their lives" but were healthy and weren't dwarfs.

The results seen by deleting the S6K1 gene mimic the anti-aging effects of caloric restriction seen in lab tests on animals -- but without dieting, Selman and colleagues observed.

The researchers conclude that thwarting the S6K1 gene might lead to treatments for aging-related diseases. However, they haven't studied the gene in people.