Although embryonic stem cells currently enjoy the public limelight and show great pr- ise for cell based medical therapies, it is the adult stem cells which are responsible for the body's natural ability to fght disease, heal and recover, or fail and succumb to various maladies. The study of mammalian adult stem cells has surged recently, most likely from a maturation of stem cell studies in the classical developmental model organisms and in hematopoeisis. All the tissues of the body examined so far are generated and regenerated from stem cells, it has been an important frst step to adapt or...