A ROVING snippet of DNA has been used to make reprogrammed stem cells that are stripped of potentially cancer-causing genes.
The first reprogrammed stem cells – known as induced pluripotent stem cells – were made by Shinya Yamanaka of Kyoto University in Japan. He used viruses to insert four genes into the chromosomes of adult skin cells, reprogramming them into an embryonic state. These iPS cells could turn into any of the body’s tissues, but cells derived from them were not transplantable into people because viruses can add extra copies of cancer-causing genes to the chromosome.
Now two teams, led by
