Click here for a special offer. Click here for our free newsletter. With perhaps 100 cows having been cloned since Dolly burst upon the scene in 1997, cattle copying is almost commonplace today. What sets these four new bulls apart is the technique used to create them. If it pans out, it may be possible not just to duplicate an animal but to actually design a better one.
Conventional wisdom is that successful cloning requires fresh cells.
But scientists at the University of Connecticut have come up with a way to clone animals from cells that have been grown in the lab for months. The team began by scraping skin cells from the ear of a prized, if geriatric, bull. They then grew the cells in culture, supposedly dooming them for cloning. But to the researchers' shock and delight, the old cells worked, producing four healthy bulls. The use of cultured cells would allow scientists to tinker with the cells' genes before cloning a new animal.