Tautipotency refers to the ability of a single cell to develop into a complete organism, possessing the potential to differentiate into all cell types necessary for forming an entire organism. This characteristic is most commonly associated with the fertilized egg or zygote, which can give rise to all tissues and organs. In plant Biology, certain cells can also exhibit tautipotency, allowing them to regenerate into a whole plant under appropriate conditions. Overall, tautipotency is a crucial concept in developmental biology and regenerative medicine.