The genome of a skin cell can be manipulated to reverse its developmental clock, resulting in a cell identical to an embryonic stem cell.

1. Four genes, Oct4, Sox2, c-Myc, and Klf4, are encapsulated into separate viral vectors and inserted into the nucleus of a skin cell.
2 .Each of these four genes lands randomly on a chromosome.
3. Each new gene integrates into the genome, and starts acting like a normal gene.
4. These four genes end up affecting the entire genome of the skin cell to such an extent that its developmental clock is reversed. Soon, the skin cell is transformed and becomes virtually identical to an embryonic stem cell.

Image: Christina Ullman