Some fear that pig viruses could jump species. Credit: ED ECKSTEIN/CORBIS

The Roslin Institute in Edinburgh — where Dolly the sheep was cloned — has been working to create transgenic pigs as a source of organs for transplant to humans. But the future of such efforts appeared in doubt this week, following comments by researcher Ian Wilmut that Geron Bio-Med intended to cut back on the research.

Wilmut said that the California-based company — which was created by the purchase of the Roslin Institute's commercial arm Roslin Bio-Med by the US biotech company Geron (see Nature 399 , 92; 1999) — was concerned about the risks that xenotransplantation might create viral diseases in humans.

But Grahame Bulfield, director of the Roslin, told Nature on Monday that Wilmut was speaking in a personal capacity. In comments later confirmed by Geron Bio-Med he added that if the company were to abandon xenotransplantation work, it would be purely on the grounds of refocusing research priorities, and not viral risk.