Two scientists in Norway have discovered that comb jellies from the species Mnemiopsis leidyi reverse from a mature lobate, or adult with lobes, to an early larval-state — when stressed — just like the immortal Turritopsis dohrnii.
- They show that reverse development can occur also in non-cnidarians, so expanding the range of body plans that are able to do it.
- It’s not the first time that scientists have made a discovery bout the “immortal jellyfish.” In the 1980s two young scientists found that when adult Turritopsis dohrnii jellyfish were stressed, they reverted to an earlier stage in their life-cycle — rather than die.
- Normally, the adults (medusae) release a free-swimming larval stage of the organism known as planulae. The planulae form polyp colonies, and those colonies eventually release new medusae.
- Both Turritopsis dohrnii and Mnemiopsis leidyi are jellies, but they belong to different groups, cnidarians and ctenophores, and each have different body plans.
- So different structures, or what scientists call morphological features.
- Turritopsis dohrnii are cnidarians, Mnemiopsis leidyi are ctenophores.
About Cnidarians
- Cnidarians have long been considered simple animals in spite of the variety of their complex life cycles and developmental patterns.
- Besides their high regenerative and asexual-reproduction potential, a number of cnidarians can undergo ontogeny reversal, or reverse development: one or more stages in the life cycle can reactivate genetic programs specific to earlier stages, leading to back-transformation and morph rejuvenation.
- The Phylum Cnidaria includes such diverse forms as jellyfish, hydra, sea anemones, and corals.
(Source: Indian Express and others)
