Dolly, Polly, Gene - send in the clones.

The cloning craze continues. With press releases, press conferences, and photo opportunities, but not peer-reviewed scientific publications, two biotech firms recently announced apparently major advances in cloning technology.

The researchers who brought the world a sheep named Dolly, the first mammal cloned from an adult cell, now say they have used similar cloning techniques to create Polly, a lamb that contains a human gene. Working not with adult cells but with fetal cells, which are easier to manipulate genetically, scientists from PPL Therapeutics and the Roslin Institute in Edinburgh adapted their method of nuclear transplantation (SN: 4/5/97, p. 214) to create the transgenic animal.

While other methods of adding human genes to mammals already exist, the investigators contend that their patented cloning technique will be more efficient. PPL Therapeutics intends eventually to create transgenic animals that produce therapeutic proteins in their milk. The company has so far declined to say which human gene they have added to Polly.

ABS Global, a biotech firm in DeForest, Wis., followed the news about Polly with an announcement that its scientists had for the first time successfully cloned a bull, named Gene and now 6 months old, from fetal cells. The company also claims that it has cows pregnant with embryos cloned from adult cells, but it notes that its cloning method differs in many details from that used by the creators of Dolly.