Courtesy of Cecil Fox and the National Cancer Institute
Differentiation, the stepwise specialization of cells, and transdifferentiation, the apparent switching of one cell type into another, capture much of the stem cell spotlight. But dedifferentiation, the developmental reversal of a cell before it reinvents itself, is an important process, too. This loss of specialization is believed to factor heavily into stem-cell culture techniques and pathological conditions such as cancer. Determining its programming, however, or even definitively identifying the process defies best efforts and flies in the face of Occam's razor: Here, the simplest explanations hardly seem sufficient.
"Dedifferentiation is difficult to look at, but the term is used fairly widely," says Rod Bremner, a senior scientist in the division of cell and molecular biology at the Toronto Western Research Institute. Many times, it seems, dedifferentiation is inferred as the mysterious means to an observable end.
The classic example of dedifferentiation ...
