Many tissues, such as skin and hair follicles, regenerate constantly throughout an organism’s lifetime, fueled by what are known as somatic stem cells. In contrast to germline stem cells, which give rise to eggs and sperm exclusively, somatic stem cells can differentiate into many types of tissues.
But hydras, miniscule freshwater animals that reproduce both sexually and asexually, are unique: their somatic stem cells don’t age. As a result, not only can the tiny organisms easily regenerate themselves after damage, they are also essentially immortal—given the right conditions, they live forever.
Read the full, original story here: Stem Cells Open Up Options