What makes a stem cell pluripotent, or an embyronic stem cell totipotent, able to form all other cell types? It has to be down to the mechanisms of genes and proteins, and researchers are working to understand those mechanisms: scientists have "identified a network of hundreds of genes that keep embryonic stem cells in their characteristic malleable state, able to develop into any cell type when the time comes. The finding, based on studies of mouse cells, provides valuable insight into the way stem cells function, and could help researchers find ways to reprogram adult cells for therapeutic use. ... there has been a recent explosion of interest in reprogramming skin or other developed cells to act like stem cells, with the ultimate goal of treating disease. But currently, he said, the process is still essentially a "black box." ... You add genes, and the cells reprogram. What happens in between? ... This kind of work provides the materials to get a better understanding of that process. The goal is to be able to manipulate cells in a very directed way."