Human-Like Brain Found in Worm

By JENNIFER VIEGAS - DISCOVERY NEWS
Added: Fri, 03 Sep 2010 14:30:03 UTC

Thanks to sdando for the link

For the first time, a structure comparable to our cerebral cortex has been found in an invertebrate -- a humble marine ragworm.

THE GIST

A marine ragworm has brain structures that researchers now believe are directly related to the human brain.

Other invertebrates likely also possess the brain structures, which correspond to our cerebral cortex.

The origins of the human brain can now be traced back at least 600 million years, when we last shared a common ancestor with marine ragworms.

Brain structures directly related to the human brain have just been identified in a marine ragworm, according to a paper published in the latest issue of the journal Cell.

The discovery means that the origins of the human brain can now be traced back at least 600 million years, when we last shared a common ancestor with this species, Platynereis dumerilii, a relative of the common earthworm.

"This worm lives in self-made tubes, explores its environment actively for food, and shows signs of learning behavior," lead author Raju Tomer told Discovery News. "Therefore, we thought this ragworm would be the ideal candidate to look for the counterparts of vertebrate higher brain centers in invertebrates."

Tomer, a scientist at the European Molecular Biology Laboratory (EMBL), and his colleagues suspect that other invertebrates, such as insects, spiders, crustaceans and velvet worms likely also possess the brain structures, called "mushroom bodies," which correspond to our cerebral cortex. The cerebral cortex is a part of the human brain involved in memory, learning, thought, language, consciousness and more.

Tomer and his team used a new technique they developed, called "cellular profiling by image registration," to investigate a large number of genes in the marine ragworm's compact brain. The method enabled the scientists to determine each cell's molecular fingerprint, and to define cell types according to the genes they express, rather than just based on their shape and location, as was done before.

"The development and patterning mechanisms of annelid mushroom bodies and vertebrate brains are too similar to be explained by independent origins," Tomer said. "They must share a common evolutionary precursor, though less complex, which evolved in the last common ancestor more than 600 million years ago."
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TAGGED: BIOLOGY, EVOLUTION, GENETICS