Working with flatworms, they've discovered a gene that makes certain the flatworm's brain develops in its head. When that gene is inactivated, the flatworm develops brain material throughout its body, including its tail.
The study, which appears in tomorrow's issue of Nature, "may help us to understand how we can rebuild organs and tissues after injury, disease or aging," the study authors write.
The flatworm gene is called ndk. That's short for "nou-darake", which is Japanese for "brains everywhere."
The researchers say the gene is present in humans. However, in humans this gene probably doesn't play a role in programming the brain to stay inside the skull. Instead, the gene likely has some other role in the development of the nervous system in human embryos, says study co-author Alejandro Sanchez Alvarado, a developmental biologist at the University of Utah School of Medicine.
Flatworms are simple organisms that live in fresh and ocean water and soil. Also known as planarians, they're about a quarter inch long. To reproduce, they attach their tail to a solid object and then swim away. The head and upper body detach from the tail.
The head and upper body grow a new tail, and the tail regrows a head. The same thing happens when a flatworm is chopped into pieces. Each piece grows into a new worm. Some of the processes involved in this kind of regeneration are similar to embryo development.
Here's where to go to learn more about the brain and spinal cord.