Which animal families have immortal members?

Photo: © Tony Wills / CC BY-SA 4.0 via iNaturalist.NZ

Which animal families have immortal members?

The immortal jellyfish and the turritopsis nutricula (a type of hydra) are the only two biologically immortal animal species known to science.

How Come?

Scientists at the Spanish University of Oviedo mapped the genetic sequence of the immortal jellyfish, able to repeatedly revert to an immature stage after reproduction. The study, published on Aug. 29, 2022, in the Proceedings of the National Academy of Sciences, found that the immortal jellyfish genome may be better at copying and repairing DNA and maintaining the ends of chromosomes intact.

How is that different from human DNA?

In humans and other species, the ends of chromosomes become so short with age that the cell can no longer divide successfully and dies.