LONDON - The Roslin Institute was awarded two UK patents on the cloning technology used to create Dolly the sheep, confirming the novelty of the technique, and bolstering the commercial position of its two licensees, PPL Therapeutics plc and Geron Corp.

The two patents, GB 2318578 and GB 2331751, cover broad generic claims to methods of nuclear transfer in which the nucleus of a quiescent donor cell is transferred into a recipient cell. The claims also cover the use of the technology in the therapeutic cloning of human cells and the production of transgenic animals by nuclear transfer.

A notice of allowance also has been received from the U.S. Patent Office for the patent application relating to the same technology.

Grahame Bulfield, director of the Roslin Institute in Edinburgh, says the quiescence technology was the breakthrough that resulted in Dolly, and he said the work of other cloning researchers is covered by the patents. "Other research groups have produced cloned sheep, cows, mice and goats and to date, there is no convincing evidence yet published that clones have been produced by nuclear transfer from other than quiescent cells."

PPL Therapeutics, also based in Edinburgh, has an exclusive worldwide license for uses in the production of pharmaceutical proteins in the milk of ruminants and rabbits, and for nutraceutical applications. Geron, of Menlo Park, Calif., acquired rights to all other applications, excluding use in human reproductive cloning, when it bought Roslin Biomed, the commercial arm of the institute, last year.

PPL has developed the technology further, with the birth in 1997 of Polly, the first transgenic sheep clone, and Cupid and Diana, born in 1999, the first cloned sheep with targeted gene insertion. Previously, the site of addition of a gene was entirely random and in a different position for every transgenic animal.