From the Technology Review: "While all animals can regenerate tissue to a certain extent - we can grow muscle, bone, and nerves, for example - salamanders and newts are the only vertebrates that can grow entire organs and replacement limbs as adults. When a leg is lost to injury, cells near the wound begin to dedifferentiate, losing the specialized characteristics that made them a muscle cell or bone cell. These cells then replicate and form a limb bud, or blastema, which goes on to grow a limb the same way that it forms during normal development. Scientists have identified some of the molecular signals that play a key role in the process, but the genetic blueprint that underlies regeneration remains unknown. Researchers hope that by uncovering these molecular tricks, they can ultimately apply them to humans to regrow damaged heart or brain tissue, and maybe even grow new limbs. ... One of the key questions yet to be answered is whether the salamander has unique genetic properties that enable regeneration, or whether all animals have that innate capability. ... If we come up with some totally unique gene only present in [salamanders], that would make it really hard to replicate."