It Was Long Thought That Cell Differentiation Was Irreversible,i

Essay

It was long thought that cell differentiation was irreversible,i.e.,once a cell like a fibroblast,a white blood cell or a cartilage cell has differentiated,it could not revert to any other cell type.Surprisingly,this is not the case.Shinya Yamanaka and his colleagues have succeeded in reprogramming a fully differentiated mouse cell,specifically a type of connective tissue fibroblast,into a pluripotent stem cell.How was this stunning feat accomplished? How did they demonstrate that iPS cells were indeed pluripotent?