Real-life hydra regrow their heads, new research details how

Hydras are a group of small aquatic animals capable of regenerating their heads, the mechanism for which has been uncovered in a new paper published in Genome Biology and Evolution.

Hydras come from the same family of animals consisting of roughly ten thousand species that fall into two major groups, Anthozoa and Medusozoa. Anthozoa comprises sea anemones, corals, and sea pens, while Medusozoa comprises sea wasps, jellyfish, and hydra. Hydras live in temperate, tropical environments, and their stem cells have the capacity for unlimited self-renewal, lending them biological immortality.

Researchers have found multiple genes associated with head regeneration for hydra but have yet to understand the regulatory networks responsible for regeneration in hydras and other regenerating species. Researchers found that epigenetics, changes in gene expression in response to environmental changes, were responsible for regeneration.

They found multiple regulatory elements within the genome that cellular machinery remodeled during regeneration to allow transcription factors to access the necessary DNA. Interestingly, the researchers found that the processes enabling head regeneration were different from those that grow the head initially, despite the same end product.

"Even though the result is the same (a Hydra head), gene expression is much more variable during regeneration. Accompanying dynamic gene expression is dynamic chromatin remodeling at sites where developmental transcription factors bind. These findings suggest that complex developmental enhancers were present before the Cnidaria and Bilateria split," said Aide Macias-Munoz, the paper's lead author.

You can read more from the paper here.