An anonymous reader writes British scientists have produced the first working organ grown from scratch in a living animal. Reprogrammed cells created in a lab were used in a mouse to produce a thymus. The organ was created using connective tissue cells from a mouse embryo and were converted into a different cell strain by changing a genetic switch in their DNA. The resulting cells grew into the whole organ after being injected. It has only been tested on mice so far, but researchers at Edinburgh University say that within a decade the procedure could be effective and safe enough for humans. The findings were published in Nature Cell Biology.