Human skin cells have been reprogrammed by two groups of scientists to mimic embryonic stem cells with the potential to become any tissue in the body.
The breakthrough promises a plentiful new source of cells for use in research into new treatments for many diseases.
Crucially, it could mean that such research is no longer dependent on using cells from human embryos, which has proved highly controversial.
The US and Japanese studies feature in the journals Science and Cell.
The Japanese team used a chemical cocktail containing just four gene-controlling proteins to transform adult human fibroblasts - skin cells that are easy to obtain and grow in culture - into a pluripotent state.
The cells created were similar, but not identical, to embryonic stem cells, and the researchers used them to produce brain and heart tissue.
After 12 days in the laboratory clumps of cells grown to mimic heart muscle tissue started beating.
- Therapeutic cloning produces stem cells which can develop into different types of body cell, making them ideal for research into treatment of disease.
- But this technology involves the creation and destruction of embryos, which is ethically controversial. The stem cells created also run the risk of being rejected by the body.
- The new technology, nuclear reprogramming, creates stem-like cells from the patient's own cells, avoiding both these problems.