Turritopsis dohrnii (immortal jellyfish)

The Turritopsis dohrnii is a type of jellyfish that can regenerate its cells when faced with a life-threatening crisis, earning it the nickname "immortal jellyfish." After reaching adulthood, the organism can revert to its earliest stage of development in response to physical damage or starvation and begin its life cycle again. The process may be compared to a butterfly transforming back into a caterpillar or a chicken turning back into an egg and hatching again. The species was discovered in the Mediterranean Sea in 1883, but its ability to reverse aging was not observed until the 1990s. Scientists have continued to study the creature in hopes of replicating the process to determine how to recycle damaged cells in the human body and cure diseases such as cancer.

Life Cycle

Turritopsis dohrnii has also been referred to as the "Benjamin Button jellyfish" (after the short story and subsequent film character who ages backward). It develops from a fertilized egg into a planula (larva). The planula attaches to the ocean floor, where it grows into a blob-like state known as a polyp colony. The polyps form into free-swimming medusae that reach the adult stage in a few weeks. Fully grown Turritopsis dohrnii are tiny, the size of a human pinky nail at about 0.18 inches (4.5 mm). They have bright red stomachs that can be seen through their nearly transparent bell-shaped bodies. They also have dozens of white tentacles that outline their bodies.

WhenTurritopsis dohrnii is physically harmed or facing starvation, it can survive through a unique process known as transdifferentiation. It has a "rebirth" and transforms back to the beginning of its life cycle as a polyp. In the span of a few weeks, the polyp releases medusae that are genetically identical to the original jellyfish. During this process, the jellyfish absorbs its cells and then recycles them into other types of specialized cells, such as turning muscle cells into nerve cells. Despite their ability to regenerate, Turritopsis dohrnii are very fragile and often fall victim to predators. The transdifferentiation process only occurs after the jellyfish has reached sexual maturity, leaving it vulnerable before that stage.

Importance to Science

The process of transdifferentiation is important to scientists and researchers because it is identical to the process that occurs in human stem cells. During transdifferentiation, an adult cell, which is specialized for a particular type of tissue, can transform into a different type. By harnessing this power, scientists could essentially replace damaged cells with new cells and possibly affect the aging process and cure disease. While scientists have been studying Turritopsis dohrnii for several decades, they still do not know exactly how it ages in reverse. Some studies, including one published in 2022, have focused on the DNA of Turritopsis dohrnii. The 2022 study found that the jellyfish had several duplicated genes, some of which could specifically repair and protect the creature's DNA, which could be activated or go dormant depending on the stage of the life cycle it is in. They posit that this process could be key to understanding the jellyfish's transdifferentiation. Despite these findings, scientists still have much to learn about Turritopsis dohrnii, and they continue to study the species as well as the potential for transdifferentiation in other jellyfish.

Bibliography

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Greenwood, Veronique. "This Jellyfish Can Live Forever. Its Genes May Tell Us How." The New York Times, 6 Sept. 2022, www.nytimes.com/2022/09/06/science/immortal-jellyfish-gene-protein.html. Accessed 8 Jan. 2026.

"The Immortal Jellyfish." American Museum of Natural History, 4 May 2015, www.amnh.org/explore/news-blogs/on-exhibit-posts/the-immortal-jellyfish. Accessed 8 Jan. 2026.

Richnov, Nathaniel. "Can a Jellyfish Unlock the Secret of Immortality?" New York Times, 28 Nov. 2012, www.nytimes.com/2012/12/02/magazine/can-a-jellyfish-unlock-the-secret-of-immortality.html. Accessed 8 Jan. 2026.

Sottosanti, Karen, and John P. Rafferty. "Immortal Jellyfish." Britannica, 30 Oct. 2024, www.britannica.com/animal/immortal-jellyfish. Accessed 8 Jan. 2026.

Than, Ker. "'Immortal' Jellyfish Swarm World's Oceans." National Geographic, 29 Jan. 2009, www.nationalgeographic.com/animals/article/immortal-jellyfish-swarm-oceans-animals. Accessed 8 Jan. 2026.

"Turritopsis dohrnii." Smithsonian, invasions.si.edu/nemesis/species_summary/-502. Accessed 8 Jan. 2026.