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'Aliens of sea' provide new insight into evolution

AP Medical Writer

WASHINGTON (AP) -- 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 gooseberry, the nickname for a comb jelly species known as Pleurobrachia bachei. They also decoded gene activity of nine additional species of ctenophores - the scientific name for comb jellies. (The "c" is silent.)

First, they found comb jellies represent the oldest branch of the animal family tree - not the simpler sea sponges traditionally thought to hold that spot, the team reported. That bolsters a similar finding published last December by competing scientists from the National Institutes of Health, which had been greeted with some skepticism.

And it's important in this context because sponges don't have neurons.

So what happened? Parallel evolution, Moroz proposed: While other branches of the animal family tree shared one path, the comb jellies essentially went down another street as they developed circuits of neurons, nerve cells that control such functions as motion and behavior. They simply don't have many of the genes that other animals use for neural development and function.

The results were "really weird," Moroz said. "Everybody from jellyfish to us have the same alphabet" when neurons communicate - but not the more ancient comb jellies.

For example, ctenophores don't use serotonin, dopamine and other common signaling chemicals, called neurotransmitters. Instead, they use methods unique to them.

"They're presenting data that's quite powerful," said biologist Antonis Rokas of Vanderbilt University, who wasn't part of the new work.

"It's almost like evolution has given us two different blueprints for building a structure that's very important," he added. "If your goal is to make a nervous system, it doesn't matter what the parts are in some ways. You could potentially mix and match. The more parts you have, the more solutions."

Join the discussion

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sylvabugg2 May 25 2014 at 1:39 AM

I know some people who could use the ability to grow a brain. One of them sits in the White House.

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6 replies
necropolis83666 May 24 2014 at 7:48 PM

They are how they are because god made them that way. 'nuff said.

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7 replies
rkhaber May 24 2014 at 5:33 PM

Remember in the oceans we are the Aliens

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1 reply
brenhatestwinkie rkhaber May 24 2014 at 6:25 PM

We are on the food chain!

Flag Reply 0 rate up
diempostdiem May 24 2014 at 6:04 PM

HP is a little late on this article. It's been on Fox for over a week.

Flag Reply +4 rate up
2 replies
jeffc152 diempostdiem May 25 2014 at 3:50 PM

Oh, were they talking about how oil spills and other pollution in the oceans are actually good for them?

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prgrsiv diempostdiem May 26 2014 at 1:44 AM

.........who'd FOX blame for it....?????????

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john4law May 24 2014 at 4:33 PM

The only place we are going to find and examine "alien" life in my lifetime at least is HERE on Earth. There must be any number of alternative ways of doing basic life functions that we just haven't discovered yet. Most micro organisms CAN'T be cultured which means we have NO idea how most living creatures actually function.

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4 replies
amanda May 24 2014 at 8:03 PM

So beautiful....

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1 reply
jimjits amanda May 25 2014 at 7:35 PM

Well thank you Amanda

Flag Reply +1 rate up
badstick103 May 24 2014 at 7:10 PM

At last I understand.

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brenhatestwinkie May 24 2014 at 6:25 PM


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1 reply
netecutli brenhatestwinkie May 25 2014 at 2:23 PM

It confuses the hell out of creationists.

Flag Reply +2 rate up
1 reply
billromine netecutli May 25 2014 at 9:37 PM

Not relly it makes perfect sence!

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Me May 24 2014 at 6:43 PM

I have a green thumb.......

Flag Reply +1 rate up
opticianandynj4u May 24 2014 at 4:46 PM


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1 reply
donaldyelsnik opticianandynj4u May 25 2014 at 3:25 AM

Wierd people go into chatrooms, Liars, cheaters and flashers galore. which one are you?

Flag Reply 0 rate up
2 replies
margelpn donaldyelsnik May 25 2014 at 1:37 PM

i dont do facebook can never find things or people to talk about so count me out

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crfcron donaldyelsnik May 26 2014 at 1:07 AM

well Donald if the shoe fits then you wear it .

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