Electric eels can naturally alter the genetics of nearby organisms, a discovery by Nagoya University researchers that highlights the role of natural electricity in genetic changes.
The electric eel is the biggest power-making creature on Earth. It can release up to 860 volts, which is enough to run a machine. In a recent study, a research group from Nagoya University in Japan found electric eels can release enough electricity to genetically modify small fish larvae. They published their findings in the scientific journal PeerJ – Life and Environment.
Understanding Electroporation in Nature
The researchers’ findings add to what we know about electroporation, a gene delivery technique. Electroporation uses an electric field to create temporary pores in the cell membrane. This lets molecules, like DNA or proteins, enter the target cell.
The research group was led by Professor Eiichi Hondo and Assistant Professor Atsuo Iida from Nagoya University. They thought that if electricity flows in a river, it might affect the cells of nearby organisms. Cells can incorporate DNA fragments in water, known as environmental DNA. To test this, they exposed the young fish in their laboratory to a DNA solution with a marker that glowed in the light to see if the zebrafish had taken the DNA. Then, they introduced an electric eel and prompted it to bite a feeder to discharge electricity.
Electric Eels: Natural Agents of Genetic Change
According to Iida, electroporation is commonly viewed as a process only found in the laboratory, but he was not convinced. “I thought electroporation might happen in nature,” he said. “I realized that electric eels in the Amazon River could well act as a power source, organisms living in the surrounding area could act as recipient cells, and environmental DNA fragments released into the water would become foreign genes, causing genetic recombination in the surrounding organisms because of electric discharge.”
The researchers discovered that 5% of the larvae had markers showing gene transfer. “This indicates that the discharge from the electric eel promoted gene transfer to the cells, even though eels have different shapes of pulse and unstable voltage compared to machines usually used in electroporation,” said Iida. “Electric eels and other organisms that generate electricity could affect genetic modification in nature.”
Other studies have observed a similar phenomenon occurring with naturally occurring fields, such as lightning, affecting nematodes and soil bacteria. Iida is very excited about the possibilities of electric field research in living organisms. He believes these effects are beyond what conventional wisdom can understand. He said, “I believe that attempts to discover new biological phenomena based on such “unexpected” and “outside-the-box” ideas will enlighten the world about the complexities of living organisms and trigger breakthroughs in the future.”
The zebrafish larvae and a DNA solution were put into a small container and placed inside the tank where the electric eel produces electric pulses when it is fed by the experimenter. Credit: Shintaro Sakaki
Reference: “Electric organ discharge from electric eel facilitates DNA transformation into teleost larvae in laboratory conditions” by Shintaro Sakaki1, Reo Ito1, Hideki Abe1, Masato Kinoshita2, Eiichi Hondo1, Atsuo Iida, 4 December 2023, PeerJ – Life and Environment.