Direct Lineage Conversions: Unnatural but useful?

Classic experiments such as somatic cell nuclear transfer into oocytes or cell fusion demonstrated that differentiated cells are not irreversibly committed to their fate. More recent work has built on these conclusions and discovered defined factors that directly induce one specific cell type from another, which may be as distantly related as cells from different germ layers. These examples of lineage reprogramming raise the possibility that any cell type may be converted into any other if the correct combinations of reprogramming factors are known.