Comb Jellies Show there is More than One Way to Make a Brain

University of Florida researchers say that comb jellies took a different approach to build a complex nervous system. These "alien" creatures might help scientists reverse brain disorders such as Alzheimer's and Parkinson's disease.

Comb Jellies (belonging to the phylum Ctenophora) are fascinating; they can regenerate not only body parts, but also their brains. These organisms show that there is more than one way of making a nervous system.

Previously, other researchers had assumed that organism took a single course in building complex brain like the one found in humans. The current study challenges this idea by saying that comb jellies went on a different path to create a brain.

Indeed, science is still trying to get its head wrapped around this creature. Recently, National Human Genome Research Institute (NHGRI) scientists had reported that comb jellies are our first ancestors and are older than the "simple" sponges.

University of Florida researchers say that comb jellies are like an "alien life-form" because their structure is so different from all other organisms.

Researchers found that several genes in comb jellies are different from those seen in other animals. These organisms don't rely on serotonin, dopamine, acetylcholine or most other chemicals to control brain function. Rather, they have limited themselves to a few peptides and glutamate neural signaling along with electrical synapses.

The current research looked at the genome of Pleurobrachia bachei, the Pacific sea gooseberry along with genomic analysis of ten other species.

"Our concept of nature was that there was only one way to make a neural system. We oversimplified evolution," said Leonid Moroz, lead author of the study, in a news release. "There is more than one way to make a brain, a complex neural circuit and behaviors."

"If you met an alien you would assume it is radically different from us," Moroz added. "There is no need to wait - these aliens are in our backyard."

According to Moroz, comb jellies could help scientists explore neuro-degenerative diseases such as Alzheimer's and Parkinson's from a different perspective.

"Some ctenophores can regenerate an elementary brain - also known as the aboral organ or gravity sensor - in 3 ½ days," Moroz added. "In one of my experiments, one lobate ctenophore - Bolinopsis - regenerated its brain four times."

The study is published in the journal Nature.