Stem cell biology has established the simple but overwhelming fact that all somatic cells in the body are descendants of a single zygote cell produced by merging the sperm cell and the oocyte. Traditionally this was considered to be a one way path leading to irreversible cell differentiation that makes up all the mature organs and tissues essential for life but at the cost of being unable to regenerate damaged or aged body parts. Stem cells derived from early embryos are pluripotent, meaning that they have the potential to differentiate into any body cell type. During cell specialization the developmental potential is reduced although the genetic information is not altered.

Early break-through studies in this area provided compelling evidence that the differentiation path of a cell does not destroy genetic potential to reprogram life. By using a mature cell nucleus implanted into the frog egg Sir John Gurdon succeeded in reproducing a tadpole in 1963. The same approach was used in 1996 to produce Dolly, the first cloned animal. Ten years later, armed by the revolutionary tool box that modern molecular biology has provided in the mean time, Prof. Shinya Yamanaka was able to induce mature cells to reverse their development and become stem cells by just few pure genes, a technique now known as induced pluripotency (2006). Sir John Gurdon and Prof. Shinya Yamanaka shared the 2012 Nobel price of Medicine/physiology “for the discovery that mature cells can be reprogrammed to become pluripotent”.

Cell reprogramming has come a way now and many new improvements are emerging. Disease models in a dish and stem cell therapies are realistic goals to be achieved in the road ahead to fight lethal or devastating diseases.

The 2015 Onassis Lectures is dedicated to the fundamental properties and capacities of stem cells from simple and complex organisms. The amazing experimental strategies to harness them to regenerate human tissues in brain, heart or pancreas will be discussed. These great discoveries will allow scientists to exploit life‘s full potential and to improve human health.