Tuft University biologists have successfully induced one species of flatworm to grow the heads and brains of other flatworm species without changing their DNA. The method used only involved manipulating the proteins that control the communication between cells providing evidence that development is not solely controlled by genetic s.
For the study, which was published in the International Journal of Molecular Sciences on Nov. 24, study author Michael Levin, from Tufts, and colleagues worked using small freshwater flatworms called Girardia dorotocephala, which are known to have remarkable regenerative capacity and retain large number of neoblasts, cells that can become any cell type in the body.
Levin and colleagues decapitated the heads of the specimens and then altered their regenerating head by interrupting gap junctions, protein channels that allow cells send messages to each other by sending electrical signals.
The researchers found that they can coax the worms to develop head and brain shapes of other closely-related species. While G. dorotocephala normally has pointy head, the treatment results in some to develop rounded heads or triangular heads.
The ease by which a shape could be induced was likewise observed to be proportional to the distance of the other worm from the G. dorotocephala on the evolutionary timeline. Effecting change was found easier in closely related species, which provides evidence that the modulation of the physiological circuit could be among the tools that evolution exploited to alter the body plans of animals.
"Taken together, these data and analyses shed light on important physiological modifiers of morphological information in dictating species-specific shape, and reveal them to be a novel instructive input into head patterning in regenerating planaria," the researchers wrote in their study.
Although the changes are only temporary as the heads of the worms started to revert back to their original shape after weeks, the researchers hope that their findings could lead to birth defect treatments and regenerative medicine that aims to rebuild or replace damaged tissues and organs.
"Electrical connections between cells provide important information for species-specific patterning of the head during regeneration in planarian flatworms," said study researcher Maya Emmons-Bell, a Tufts undergraduate. "This kind of information will be crucial for advances in regenerative medicine, as well as a better understanding of evolutionary biology."
