Two monkeys 'cloned' from embryo cells.

The firestorm of discourse over cloning, ignited by the recent news that Scottish researchers had created a lamb from the DNA of an adult sheep, has been fanned by scientists who announced this week that they have created rhesus monkeys with DNA from the cells of developing monkey embryos.

While this feat does not meet the classic definition of cloning-using a cell from an adult animal to create a genetic copy-the researchers say it is the first time live primates have been generated by this method.

The purpose of the work is not to clone adult monkeys but to develop a way of producing genetically indistinguishable primates, according to a statement released by the scientists at the Oregon Regional Primate Research Center in Beaverton who conducted the as-yet-unpublished research.

Such animals would be useful in drug studies and other research projects because they would enable investigators to dismiss genetic variability as a confounding factor in interpreting their experiments. Researchers have long experimented on mice made genetically similar by generations of inbreeding. Like the sheep cloners, the Oregon scientists created their monkeys with a technique called nuclear transfer. The researchers stripped the genes from unfertilized monkey eggs and then added new genetic material by fusing each egg to a cell taken from an eight-cell monkey embryo.

This fusion sometimes tricks the egg into developing as if it had been fertilized by a sperm cell. When this occurs, researchers implant the resulting embryo into a surrogate mother monkey.

The Oregon group produced two monkeys by this method. The animals are not genetically identical to each other because two different embryos were used as sources of genetic material.