Figure 1: Image of Turritopsis Dohrnii (LINK)
Most jellyfish species have similar life cycles. They release substantial amounts of eggs into the ocean for them to fertilize. These fertilized eggs develop in a planktonic spore called a planula. And about a day later, the fertilized eggs hatch—allowing planula larvae (often described as oval-shaped and minuscule with cilia surrounding the body) to emerge from the female jellyfish’s mouth.
The planula larvae attach their body to a surface to grow into polyps, which usually spend their time feeding and eventually enter the growing process of strobilation. In this process, polyps develop into immature medusas and detach themselves from a hard surface. Freely-swimming premature medusas prosper in size and transform into adult jellyfish that live for one to three years.
Given the developmental process of jellyfish species, these sea creatures live a cycle of life and eventual death. However, the Turritopsis Dohrnii, a 4.5 millimeter-long jellyfish species, seems to live only in the former part of that cycle. In other words, a Turritopsis dohrnii’s lifespan can prolong endlessly unless it is severely damaged or consumed by predators.
Scientist Maria Pascual-Torner and her colleagues at the Universidad de Oviedo in Spain discovered that the primary reason for the species’ immorality could be because they have duplicated genes that help repair the jellyfish’s DNA. They tested their hypothesis by stimulating a rejuvenation process in the jellyfish species. Researchers let the jellyfish starve. Most of the time, starvation would eventually kill a normal jellyfish; however, the Turritopsis Dohrnii medusas shrunk, proliferated polyps, and began restoring their bodies. Examining the genes that were at play during each of the rejuvenation stages, the team discovered “a marked change in the use of genes linked to DNA storage” (Greenwood). The genes were most active in fully grown Turritopsis Dohrnii (allowing for the creation of proteins) and least active in underdeveloped polyps.
Though further research needs to be done on these genes of DNA storage, such current findings lead us a step closer to discovering a fascinating method for immortality in other animals and potentially humans.
Works Cited
Greenwood, Veronique. “This Jellyfish Can Live Forever. Its Genes May Tell Us How.” The New York Times, 6 September 2022, https://www.nytimes.com/2022/09/06/science/immortal-jellyfish-gene-protein.html. Accessed 10 December 2022.
Greenwood, Veronique. “This Jellyfish Can Live Forever. Its Genes May Tell Us How.” The New York Times, 6 September 2022, https://indianexpress.com/article/technology/science/immortal-jellyfish-turriptosis-dohrnii-genes-8135693/. Accessed 10 December 2022.
“The "Immortal" Jellyfish That Resets When Damaged | AMNH.” American Museum of Natural History, 4 May 2015, https://www.amnh.org/explore/news-blogs/on-exhibit-posts/the-immortal-jellyfish. Accessed 10 December 2022.
“Jellyfish Life Cycle: Introduction, Life Cycle, FAQs - Biology.” BYJU'S, https://byjus.com/biology/jellyfish-life-cycle/. Accessed 10 December 2022.
“Meet the Only Immortal Animal on Planet Earth.” Earthly Mission, https://earthlymission.com/immortal-species-jellyfish-age-backward-turritopsis-dohrnii/. Accessed 10 December 2022.
Q & A
David: How do the Turritopsis Dohrnii jellyfish differ from other jellyfish, in other aspects other than its immortality? Is its diet, habitat, and survival patterns also different?
The most significant difference between the Turritopsis Dohrnii jellyfish and other jellyfish is that the Turritopsis Dohrnii jellyfish is immortal. Regarding diet, both this jellyfish species and others are carnivorous—feeding on tiny sea creatures like plankton, fish eggs, and even other jellyfish. As for habitat, the Turritopsis Dohrnii can be found in any ocean around the world (though they originated in the Mediterranean Sea) but prefer to live in warmer waters. Other jellyfish species can be located in supposedly cold and warm ocean water as well. Lastly, because jellyfish—overall—comprise approximately 98 percent of water (transparency), they can easily camouflage with their surroundings.