“The Curious Case of the Immortal Jellyfish”

The Curious Case of the Immortal Jellyfish

hydrozoaIt’s official: the only thing certain in this world is taxes. That’s because death, for a tiny sea creature, is not inevitable. Turritopsis nutricul, a jellyfish-like hydrazoan, is the only animal known to be potentially immortal.

Once it reaches sexual maturity, Turritopsis looks like a tiny, transparent, many-tentacled parachute (only about 5mm in diameter) that floats freely in warm ocean waters. But when times get tough, Turritopsis can turn into a blob, anchor itself to a surface, and undergo a sort of reverse methamorphosis back to its youthful form as a stalk-like polyp. That’s like a butterfly turning back into a caterpillar. Scientists, who first described this phenomenon [pdf] in the 1990s, believe Turritopsis can repeat its life cycle indefinitely.

The trick to Turritopsis‘ infinite do-overs is a process called transdifferentiation, which turns one type of cell into another. While other animals can undergo limited transdifferentiation to regenerate organs (salamandars can regrow limbs, for example), Turritopsi is the only one that can regenerate its entire body.

Not surprisingly, the immortal Turritopsi are spreading. Native to the Caribbean oceans, Turritopsi have now been identified in waters near Spain, Italy, Japan, and the Atlantic side of Panama. Even though specimens from different locations have different numbers of tentacles (from 8 to 24), genetic tests confirm that they are of the same species. Researchers believe the creatures are criss-crossing the oceans by hitchhiking in the ballast tanks of large ships.

Image: Maria Pia Miglietta


http://www.stumbleupon.com/su/32bDOu/blogs.discovermagazine.com/discoblog/2009/01/29/the-curious-case-of-the-immortal-jellyfish/

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4 responses to ““The Curious Case of the Immortal Jellyfish”

  1. Very interesting!
    I thought there was a limit on the number of times a cell can divide. Something about the DNA breaking at the ends. Sorry I don’t remember the specifics.
    I understand that it can revert back to a polyp stage but it still has to replace cells … right?

  2. Megan, you’re thinking of telomeres. Perhaps this thing gets to reset its telomeres every time it cycles back and forth through its life stages? Amazing! Hope it doesn’t take over the planet, though.

  3. I wonder if the transdifferentiation is limited,or they just think that if they reverse the methamorphosis that it is immortal?

  4. If these jellyfish are essentially “immortal” (I’m assuming they can still be killed via dessication or predation), why hasn’t the population increased exponentially since the species came about? I agree with Dr. Leupen–I hope these things don’t take over the oceans because it seems like we could have an outbreak gearing up at any moment!

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