Cloned cows provide company for Dolly.

In the two years since she was born. Dolly probably has never worried about being the only mammal ever cloned from the DNA of an adult cell. But for some scientists trained to accept no result unless it can be duplicated, the sheep's singular life has been disquieting.

News from the Ishikawa Prefectural Livestock Research Center in Ishikawa Ken. Japan should cause such skeptical souls to sign in relief. Scientists there announced this week the birth of two calves created by the cloning of cow cells.

In a process called nuclear transplantation, which was also used to create Dolly (SN: 4/5/97 p. 214/, the researchers reportedly fused cells from an adult cow's uterus to cow eggs whose own DNA had been removed. The substitute DNA from the uterine cells guided me eggs as they developed in/o embryos, which were then implanted into live surrogate mothers. The mothers each harboring two embryos, were due m mid-August but one gave birth prematurely on Sunday, the Japanese group announced.

"This would be the first confirmation of adult donor cells working," says George E. Seidel Jr. of the Animal Reproduction and Biotechnology Laboratory at Colorado State University in Fort Collins.

Seidel and other scientists note that it's difficult to judge the legitimacy of me new cloning work given the few details released so far. The Japanese group has nor yet publicly described the genetic tests conducted to confirm that their newborn calves are indeed clones, and it has not published a report on the experiment.

"I hope it's correct. It's exciting if it is. but we need more information before making any definitive conclusions." notes cloning researcher James M. Robl of the University of Massachusetts tn Amherst.

This week's announcement from Japan may have stolen thunder from another cloning effort, if the scientific rumor mill is to be believed. For several months, gossip has circulated among scientists that a research team headed by Ryuzo Yanagimachi of the University of Hawaii School of Medicine in Honolulu has cloned mice from adult mouse cells.

According to media reports, Yanagimachi hinted at the accomplishment at a recent meeting but did not provide details. When contacted by Science News. Yanagimachi declined to comment other than to note that a paper describing his group's research would appear this month in a scientific journal.

New cloning reports may nor put to rest all doubts about Dolly--some investigators have speculated that she was inadvertently cloned from a fetal rather man adult cell. They should. however, resolve the issue of whether cloning from adult cells is possible.

Still the practical significance of this type of cloning remains unclear. Researchers can develop many of cloning's applications, such as the addition of human genes to animals, without the use of adult cells.

Last year, the investigators who created Doily unveiled Polly a lamb cloned from fetal sheep cells to which a human gene bad been added SN: 8/23/97, p. 127). And in the May 22 SCIENCE. Robl and his colleagues describe genetically altered calves similarly cloned from fetal cow cells.