Jellyfish is anatomically sophisticated

A U.S. study says the anus-less, headless, heartless, gutless, back or front-less jellyfish is really a remarkable genetically sophisticated creature.

Scientists at Dartmouth College in Hanover, N.H., say beneath the seemingly simple exterior of the jellyfish and its relatives, known as cnidarians, lies an amazing collection of genes including many that give rise to humans' complex anatomy, The New York Times reported Tuesday.

Lead researcher, Kevin J. Peterson, a Dartmouth biologist, said, "This data have made a lot of people step back and realize that a lot of what they had thought about cnidarians was all wrong."

Cnidarians developed with their body parts growing from two primordial layers of tissue. Other animals, including humans, have a third layer of embryonic tissue which gives rise to muscles, the heart and other organs not found in cnidarians, the Times reported.

In a paper to be published in the journal Paleobiology, Peterson and his colleagues propose that once water began to fill with animals, the earliest cnidarians anchored themselves to the sea floor and grew upward.

In the process, they abandoned the body plan of their ancestors, the Times reported. Around the same time, cnidarians evolved their weaponry -- a cell containing a miniature harpoon for paralyzing prey with toxins.

Copyright 2005 by United Press International