Researchers from Tufts University have published a study that has successfully used flatworms to grow the heads and brains of other flatworm species without altering their genetics, as outlined in the press release.

The findings reveal that the genome does not hard wire head shape and can be overridden through the manipulation of bioelectrical networks in the body. Although it has long been known that networks in the brain can exploit electrical synapses in order to rewrite information in the brain, this is the first experiment to use this knowledge to induce one species to grow characteristics of another.

"It is commonly thought that the sequence and structure of chromatin - material that makes up chromosomes - determine the shape of an organism, but these results show that the function of physiological networks can override the species-specific default anatomy," said Michael Levin, senior author of the study.

Using the flatworm Girardia dorotocephala, the researchers induced the development of head shapes that were specific to other species of flatforms by interrupting gap junctions, the protein channels that allow cells to pass electrical communication signals to each other. These interruptions not only changed the head shape of the worm but also altered the distribution of its adult stem cells.

"By modulating the connectivity of cells via electrical synapses, we were able to derive head morphology and brain patterning belonging to a completely different species from an animal with a normal genome," Levin said.

The findings are important because biologists could use them to learn how to modify birth defects and successfully grow new body parts after injury.

"These findings raise significant questions about how genes and bioelectric networks interact to build complex body structures," said Levin.