1.   But a transient activation, just long enough to rebuild the telomeres, should present no problem.

2.   But perhaps the gene could be flicked on just long enough to rebuild telomeres.

3.   Rather, the hope is to develop drugs that will switch on telomerase temporarily, just long enough for it to rebuild the telomeres back to their youthful length.

4.   Telomerase is like a tiny molecular carpenter that rebuilds telomeres as they shorten.

5.   Though all cells possess the genes to make telomerase, the enzyme that rebuilds shortened telomeres, in most cells the critical telomerase gene is permanently switched off.