A monster with multiple heads? That sounds like something straight from our comic book fantasies. However, science has once again proven that nothing is impossible.
In the ancient Greek mythology, Hydra is a mythical beast that can grow two heads to replace a head that was lost. It turns out, the real-life animal named after the monster can also grow multiple heads. With a single genetic tweak, scientists were able to create monstrous hydras that sprout heads all over their bodies
Introducing the Immortal Hydra
Hydras are invertebrates that look like tiny tubes. Usually, they have one foot attached on a long skinny body and a tentacled head. They grow only to about 10 millimeters (0.4 inches) long and are known for their regenerative abilities.
Previous studies revealed hydras constantly renew their bodies with fresh cells. Due to this, they show no signs of aging and maturation. In the wild, hydras die due to water contamination, diseases or predators. However, scientists claim that with the right circumstances, a hydra might be able to live forever.
How the Multi-Headed Hydra Came to Be
This isn’t some mad science experiment like stitching extra heads or creating chimeras. The researchers only made use of the hydras amazing regenerative abilities.
Here are the facts—Hydras can re-grow body parts. A gene called Wnt3 in hydras is known to be responsible for the growth of their head. This gene has a genetic receptor called beta-catenin/TCF. And when this gene is activated, hydras will start to grow extra heads.
What the researchers had to find was the “off” switch to prevent the hydras from growing too many heads. The idea is to “balance” the activation and the deactivation process, stated Brigitte Galliot, a professor of genetics and evolution at the University of Geneva according to Live Science.
The researchers started observing the regenerating process of hydras, as well as several of its close relatives including planarians and flatworms, which can also regenerate. They narrowed down which genes are active during head regeneration. Finally, they were able to find a protein called Sp5.
To verify their finding, the researchers grew which are hydras engineered not to express the Sp5 gene.
“We have quantified the expression of the genes encoding Wnt3 and Sp5 in different parts of the body of intact or amputated Hydra, and discovered that a regulatory loop between the two activities is established according to the location and quantity of each gene expressed,” Gallot stated.
The result is a hydra which can have multiple heads. “In 100 [percent]of these animals, you get ectopic [extra]heads… which is really amazing,” Gallot said.
She added that these heads are totally functional. They have a nervous system, a working mouth, and tentacles.
The more interesting thing is, Wnt3 isn’t just found in hydras and closely related animals. They are also present in mammals, including humans. Galliot said that Wnt3 can affect the development of embryos, which can lead to more discoveries about early human development. Also, the gene is a key factor in some types of cancer. And Sp5 manipulation might be something that could stop the development of such cancers. These types of studies are still far for now but Galliot their findings on multi-headed hydras could point out the way for future medical researches.