May 23, 2014
New Study On Comb Jellies Could Be A Zoological Game Changer
Brett Smith for redOrbit.com - Your Universe Online
A new study from a massive international team of researchers has shown that there is more than one way to “make an animal,” which could completely reshape 200 years of zoological theory.
The study focused on the genomic blueprints for 10 species of comb jellies, or ctenophores, and discovered that the simple animals developed complex organs, neurons, muscles and behaviors independently from sponges, previously thought to be the earliest animal lineage.
“This paper is also distinct from other studies because it, for the first time, unites microchemical and physiological approaches to validate genomic predictions,” said study author Leonid Moroz, a neuroscientist at the University of Florida. “By revealing the unique molecular make-up of major features – the development, immune system, nerves and muscles – I can honestly introduce you to the aliens of the sea.”
“If you met an alien you would assume it is radically different from us,” he added. “There is no need to wait – these aliens are in our backyard.”
According to the study, which was published in the journal Nature, ctenophores developed neural circuits and chemical language that are much different than the rest of the animal kingdom.
“Some ctenophores can regenerate an elementary brain — also known as the aboral organ or gravity sensor — in 3 ½ days,” Moroz said. “In one of my experiments, one lobate ctenophore — Bolinopsis – regenerated its brain four times.”
The team discovered that comb jellies are dissimilar to other animals in their neurogenic, immune and developmental genes. Numerous genes managing neural development in other animals are either missing or not expressed in comb jellies. Ctenophores also do not use serotonin, dopamine, acetylcholine or other neural transmitters that regulate brain activity in other animals. The researchers said they may use an alternative range of peptides and glutamate neural signaling, genetic switches and a diverse range of electrical synapses.
This idea of a neural system developing parallel to that of other animals’ turns approved beliefs on their head, Moroz said. The standard idea was that neural intricacy developed in a single clear-cut course: from basic nerve nets up to a human level of complexity.
“Our concept of nature was that there was only one way to make a neural system. We oversimplified evolution,” Moroz said. “There is more than one way to make a brain, a complex neural circuit and behaviors.”
The Florida neuroscientist said the study could lead to new candidates for neurogenic and signaling, and newly recognized receptors could lead to new discoveries in synthetic biology. Currently, most treatments for neurodegenerative diseases are only capable of mitigating damage – not curing the disease itself.
“What if we could not only slow the progression of Parkinson’s or memory loss in aging, but reverse it?” Moroz asked. “Ctenophores show us that there is more than one design for a complex nervous and muscular organization.”
“Nature is much more innovative than we thought,” he added.
Speaking to Nature News – Gert Wörheide, an evolutionary geobiologist at Ludwig Maximilian University in Munich, Germany, said he is skeptical about the study’s conclusion, stating that ctenophores are probably not the closest relatives of the first animals.
“I think the last word is not spoken yet on where the ctenophores go,” Wörheide concluded.