Chinese researchers said on Wednesday they had created versatile stem cells from pigs, a ground-breaking achievement that could open up new paths for combatting human disease.

Doctors led by Lei Xiao, of the Shanghai Institute of Biochemistry and Cell Biology, took adult cells taken from a pig's ear and bone marrow and reprogrammed them so that they became so-called pluripotent stem cells.

These are cells that, like the coveted stem cells found in embryos, can differentiate into any type of cell in the body.

It is a technical exploit because until now, no-one has been able to achieve reprogramming using somatic cells -- cells that do not come from sperm or eggs -- from a hooved animal.

But the main interest lies in fundamental medical research, as it offers the hope of using the pig as a test bench for disease and a source of transplant material, Xiao said.

The pig is close to the human in many biological functions and with some organs that are similar in size.

"We could use embryonic stem cells or induced stem cells to modify the immune-related genes in the pig to make the pig organ compatible to the human immune system," he said in a press release.

"Then we could use these pigs as organ donors to provide organs for patients that won't trigger an adverse reaction from the patient's own immune system."

Another possibility would be to modify genes in lines of pig stem cells so that they replicate flaws in human genes that cause diabetes and other diseases, he suggested.

The modified stem cells could then be used to generate pigs with the same disorder, thus providing researchers with a model on which to test new therapies.

The Chinese team tucked a basket of reprogramming genes inside a virus to infect the adult cells and return them to their naive, versatile state.

Tests on the cells showed they were capable of differentiating into the three fundamental layers of tissue in an early embryo.

The paper is published in the Journal of Molecular Cell Biology.

Work on similar lines is being carried out on human cells, first achieved in 2007 by Shinya Yamanaka of Kyoto University.