A recent study conducted by researchers from the University of Geneva discovered that the freshwater polyp Hydra uses genetic modification in order to reform complete fragments of its body and remain alive even after all of its neurons have disappeared, according to the university. The genetic modifications involve the overexpression of genes, some of which are involved in nervous system functions.
"We identified 25 overexpressed genes in epithelial cells, the cells forming the Hydra's coating tissues. Some of these genes are involved in diverse nervous functions, such as neurogenesis or neurotransmission," said Yvan Wenger, co-first author of the article.
Although the regenerative capabilities of the Hydra have long been known, originally discovered by naturalist Abraham Trembley more than 250 years ago, they have been poorly understood up until now.
"Hydra's loss of neurogenesis induces epithelial cells to modify their genetic program accordingly, indicating that they are ready to assume some of these functions," said Wanda Buzgariu, co-first author of the article. "These 'naturally' genetically modified epithelial cells are thus likely to enhance their sensitivity and response to environmental signals, to partially compensate for the lack of nervous system."
Understanding the nature of the Hydra's cellular plasticity can help us further understand neurodegenerative diseases as some of the animal's genetics are also important players in the processes of cellular reprogramming in mammals. Furthermore, it can shed light on the origins of the nervous system.
"The loss of neurogenesis in Hydra may provide an opportunity to observe a reverse evolutive process, because it sheds light on a repressed ancestral genetic toolkit," said Brigitte Galliot, a professor at the University of Geneva. "An atavism of epithelial cells, when they most probably also possessed proto-neuronal functions."
Despite the promise of the findings, further research into the details of these new functions must be conducted in order to understand just how Hydra's epithelial cells conduct gene overexpression in order to adapt their genetic program.