Electric eels in shocking gene transfer discovery

Eectric eels can release enough electricity to genetically modify small fish larvae. Image: Shintaro Sakaki

The electric eel is the most effective 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 also release enough electricity to genetically modify small fish larvae. They published their findings in the journal PeerJ - Life and Environment.

The researchers' findings add to what is known 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 researchers 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.

“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.”

Atsuo Lida, Nagoya University

Then, they introduced an electric eel and prompted it to bite a feeder to discharge electricity. According to Assistant Professor Atsuo Lida, who led the project alongside Professor Eiichi Hondo, 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 realised 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.

Overlayed images showing DNA of zebrafish larvae - in florescent green - that has been modified by electricity from the eel. Image: Shintaro Sakaki

“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 Lida. "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. Professor Lida says he is very excited about the possibilities of electric field research in living organisms. He believes these effects are beyond what conventional wisdom can understand.

“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.”