Planarians are a commonly studied type of flat worm. One of the things that make them so interesting is their ability to completely regenerate. If you chop a planarian in half, you’ll get two complete worms. One half will regrow its tail, and even more amazingly, the other half will grow a new head complete with brain. This is possible because a large percentage of the planarian’s cells are stem cells, which can differentiate into any required cell type.
Daniel Felix and Aziz Aboobaker of the University of Nottingham, UK, have discovered a gene specifically required for regrowing planarian brains. The gene is called Smed-prep. Smed refers to the genus of the study organism, Schmidtea mediterranea, and prep is short for an enzyme that has already been discovered in many other organisms, including humans. In other words, Smed-prep is the S. mediterranea version of the prep gene. Without Smed-prep, planarians don’t regenerate normal heads and brains. Not surprisingly, Smed-prep is predominantly expressed in the planarian head.The researchers hope that a better understanding of the genes involved in planarian regeneration will have repercussions for replacing damaged human tissues, especially if we turn out to have the same genes.