Just how old is Dolly?

28 May 1999

Just how old is Dolly?

SCIENTISTS working for the Roslin Institute have had to ask among the local farming community for their best guesses at the natural lifespan of farmed sheep.

The question was prompted by curiosity over the age of their most famous animal – Dolly the cloned sheep.

Dolly was cloned from a cell taken from the mammary gland of her mother. The question was then whether she was the age of her mother when she was born.

Scientists from PPL Therapeutics, as reported in a recent issue of Nature, have looked for clues at the end of the chromosomes called telomeres. These seemed to be linked to the number of times cells might divide in the life of the animal.

The scientists report that Dollys telomeres were slightly shorter than would be expected in a sheep of her age born naturally.

• The Guardian 28/05/99 page 2