Stanford researchers have shown that a human evolutionary ancestor, the sea squirt, can correct abnormalities over a series of generations, suggesting that a similar regenerative process might be possible in people. Missing limbs, scarred hearts, broken spines, and wounded muscles always try to repair themselves, but often the result is invalidism or disease. Even some tumors try to revert to normal, but are unsuccessful. If the genetic sequence described in the sea squirt applies to humans, this study represents a major step for regenerative medicine.
The sea squirt is more closely related to humans than many would expect. It may appear similar to a sea sponge, worm, or plant, but it is actually not closely related to any of these organisms. Sea squirt larvae have primitive spinal cords, distinguishing them in the greater chain of life and on the evolutionary ladder. Specifically, sea squirts, like humans, belong to a group of animals called chordates (organisms with some level of spinal cord development), and many scientists believe that sea squirts approximate what the very first human chordate ancestor may have been like 550 million years ago. By studying this modern day representative of our evolutionary ancestor, researchers are able to identify fundamental principles of complex processes, such as healing and organ regeneration, on which new treatments are based.