What is true of mice is often true of humans, and although scientists are a long way from being able to cause limbs to regenerate, the research is attracting attention. Jeremy Brockes, a leading expert on regeneration at University College London, said the report was “an excellent paper.” Though there is a lot still to learn about the process, “it is hard to imagine that it will not be informative for regenerative medicine in the future,” he said.

In recent years, most research in the field of regenerative medicine has focused on the hope that stem cells, immature cells that give rise to any specific type of cell needed in the body, can somehow be trained to behave as normal adult cells do. Nature’s method of regeneration is quite different in that it starts with the adult cells at the site of a wound and converts the cells to a stemlike state in which they can grow and divide.

The Stanford team has taken a step toward mimicking the natural process. “What I like is that it’s built on what’s happening in nature,” Dr. Blau said. “We mammals lost this regenerative capacity in order to have better tumor suppression, but if we reawaken it in a careful way we could make use of it in a clinical setting.”

Dr. Pomerantz, a clinician, hopes the technique can be applied to people, though many more animal experiments need to be done first. “We have shown we can recapitulate in mammalian cells behavior of lower vertebrate cells that is required for regeneration,” he said. “We would propose using it in amputations of a limb or part of a limb or in cardiac muscle.” After a heart attack, the muscle cells do not regenerate, so any method of making them do so would be a possible treatment.

Interfering with tumor suppressor genes is a dangerous game, but Dr. Pomerantz said the genes could be inhibited for just a short period by applying the right dose of drug. When the drug has dissipated, the antitumor function of the gene would be restored.