The announcement that Sir John Gurdon had been awarded the 2012 Nobel Prize for Medicine or Physiology was received with great joy by developmental biologists. It was a very special occasion because of his total dedication to science and turning the Golden Rule of western civilization - love your neighbor as yourself - into a reality in our field. This essay attempts to explain how John became ...

The ability to obtain genetically identical offspring in cattle (clones) is useful for research and for potential applications to breeding schemes. Experimental possibilities for generating such animals have evolved considerably in the last two decades. Embryo splitting has become a relatively simple technique but is limited to twinning. Embryonic nuclear transfer has improved and is associated...

Cloning mammals by nuclear transfer is a powerful technique that is quickly advancing the development of genetically defined animal models. However, the overall efficiency of nuclear transfer is still very low and several hurdles remain before the power of this technique will be fully harnessed. Among these hurdles include an incomplete understanding of biologic processes that control epigeneti...

Nuclear transfer, also referred to as cloning, attracted public attention when the first mammal, the sheep Dolly, was cloned from an adult cell. In this review, we highlight some of the milestones reached in the 50 years following the first nuclear transplantations in frogs. We also address the problems associated with nuclear transfer and provide an survey on current stem-cell technology. In t...