'Aliens of sea' are providing new insight into animal development.

AuthorNeergaard, Lauran

Byline: Lauran Neergaard

Exotic sea creatures called comb jellies may reshape how scientists view early evolution -- as their genes suggest nature created more than one way to make a nervous system.

These beautiful but little-known translucent animals often are called ''aliens of the sea,'' for good reason. Somehow, they rapidly regenerate lost body parts. Some even can regrow a very rudimentary brain.

Now in an in-depth look at the genes of 10 comb jelly species, researchers report that these mysterious creatures evolved a unique nervous system in a completely different way than the rest of the animal kingdom.

In other words, the nervous system evolved more than once, a finding published Wednesday by the journal Nature that challenges long-standing theories about animal development.

''This paper proves, on a genomic basis, they're truly aliens,'' said University of Florida neurobiologist Leonid Moroz, whose team spent seven years unraveling the genetics behind comb jellies' neural programming.

But the findings aren't just about evolutionary history. Comb jellies build a nervous system essentially using their own biological language, Moroz explained. That points to new ways to investigate brain diseases such as Alzheimer's or Parkinson's -- maybe even, one day, the ability to engineer new neurons, Moroz said.

They ''open to us completely unexpected windows,'' he said.

Moroz is exploring some of those windows using a unique floating laboratory that allows sophisticated genomic sequencing at sea. In a test run off the coast of Florida this spring, The Associated Press documented how his team is studying which genes switch on and off as iridescent comb jellies regenerate from injury.

All animals evolved from a single ancestor. Scientists want to determine which branches broke off first, and how the earliest animals gradually changed to become more complex. The general theory: The oldest animals were the simplest, and once neural systems emerged, they evolved in a straightforward path from primitive nerve nets up to complex human brains.

Moroz's team offered a dramatically different explanation.

The researchers mapped the full genetic code of the Pacific sea...

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