A team of Japanese researchers has successfully produced cloned mice from cells found in urine, according to an article published Friday in the British science journal Scientific Reports.

The discovery by researchers from the University of Yamanashi and other institutions has potential applications in breeding endangered species, as urine can be obtained without causing harm to animals.

Along with water and waste products, animal urine contains some body cells, such as from inside the urethra.

Researchers isolated certain cells in mice urine, and put the nuclei from these cells into mice egg cells that had been stripped of their nuclei. They then implanted the resulting cloned embryos into the fallopian tubes of surrogate mother mice.

Of the four mice lineages used in the experiment, two lineages produced a total of four healthy mice.

The two lineages that yielded the healthy mice had a successful birth rate of between 1 and 3 percent of the treated embryos.

Breeding the cloned mice with each other resulted in successful birth, an encouraging sign for the application of the technology in breeding programs.

Further research will focus on whether the cloned mice live as long as normal mice.

Lead researcher Teruhiko Wakayama of the University of Yamanashi said more examination is necessary to evaluate the limits of the process.

"We want to see how long after urination the cells can be used, because urine samples taken outdoors may have been sitting around for some time after leaving the body," Wakayama said.