Yamanaka Factors & Partial Cellular Programming
Prior to this discovery, scientists assumed that the egg cell (oocyte) contained a complex set of factors required to reprogram an adult somatic cell to become an embryonic one. Surely, many factors in the egg cells would be required to transform an old egg cell into a new animal. Takahashi & Yamanaka flipped this idea on its head when they proved that only four Yamanaka factors are needed to make this transformation.
The Yamanaka factors were used to reprogram adult mouse connective tissue cells (fibroblasts) back into an embryonic state known as pluripotency. This is a state in which the cell behaves similar to an embryonic stem-cell and can be any cell type within the body.
This discovery opened the door to research on how these Yamanaka factor could be used as a way to rejuvenate cells and combat age-related illnesses.