What Sea Anemones and Humans have in Common: An Ancestor with Nerve-Cell Signalling

It turns out that the genes responsible for electrical communication among nerve cells in our brains evolved a staggering 600 million years ago in a common ancestor of both humans and the sea anemone. The new findings reveal a bit more about these genes and evolution as a whole.

"Our research group has been discovering evidence for a long time that most major signaling systems in our neurons are ancient, but we never really knew when they first appeared," said Timothy Jegla, one of the researchers, in a news release. "We had always assumed that we would be able to trace most of these signaling systems to the earliest nervous systems, but in this paper we show that this is not the case. It looks like the majority of these signaling systems first appear in the common ancestor that humans share with jellyfish and sea anemones."

Electrical impulses in nerve cells are created by charged molecules, known as ions, that move into and out of the cell through ion-channel proteins that form openings in the cell membrane. In this case, the researchers examined the functional evolution of the genes that encode the proteins for potassium channels, which are ion channels that allow potassium to flow out of nerve cells, stopping the cell's electrical pulses.

"We don't yet understand why our ion channels evolved at that time, but the changes in the ability of nerve cells to generate electrical signals much have been revolutionary," said Jegla. "Our current favorite hypothesis is that neurons capable of directional signaling might have evolved at this time. If our hypothesis turns out to be correct, we may be able to gain some important insights into how nerve cells and circuits evolved by studying sea anemones."

The findings reveal a bit more about the evolution of the human nervous systems. More specifically, it may help researchers better understand neurological diseases, which are caused when the genes associated with these nerve cells mutate.

The findings are published in the journal Proceedings of the National Academy of Sciences.

For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).