Telomerase is an enzyme that lengthens the life of mice in lab studies, but how it affects human aging remains unclear. That is because of the difference in humans and mice in addition to aging and telomere biology.

Scientists from Geron Corporation in Menlo Park, California, first discovered telomeres extend from the end of chromosomes, and that they preserve the integrity of chromosomes. But as cells divide, this integrity is compromised by the shortening of the telomeres. The cellular death and damage that occur are connected to aging. Telomerase, found in germ cells and cancer cells, is shown to rebuild the telomeres.

Now scientists hope to use this discovery to reverse the effects of aging.