All they had to do, the scientists said, was add four genes. The genes reprogrammed the chromosomes of the skin cells, making the cells into blank slates that should be able to turn into any of the 220 cell types of the human body, be it heart, brain, blood or bone. For all the hopes invested in it over the last decade, embryonic stem cell research has moved slowly, with no cures or major therapeutic discoveries in sight. But with the new method, human cloning for stem cell research, like the creation of human embryos to extract stem cells, may be unnecessary.
Researchers and ethicists not involved in the findings say the work, conducted by independent teams from Japan and Wisconsin, should reshape the stem cell field.