Electric Eels’ Shocking Ability To Alter The Genetics Of Nearby Animals

06 Dec 2023 by GrrlScientist · Forbes

A new study has found that electric eels can alter the genetics of nearby animals through electrical discharges

The face of an electric eel. The massive electric organ in this species is made up of platelets of ... [+] modified muscle fibers connected in series along the body. Each electroplate generates only 0.1 volt, but up to 80% of the eel is electric organ. The total voltage generated is a function of length: the longer the organ, the greater the electrical discharge. A 9 foot (3m) eel can deliver 800 volts, more than enough to stun a man. (Credit: Travis / CC BY-NC 2.0 DEED)Travis via a Creative Commons license

Not only is the Universe stranger than we think, it is stranger than we can think.

— Werner Heisenberg

Electric eels are truly amazing creatures. They can produce enough electricity to run a kitchen dishwasher or to light up your Christmas tree, but now we’ve found that their electric pulses can also alter the genetics of nearby aquatic creatures. Yes, you read that correctly. This shocking discovery was made by a research group at Nagoya University who just reported that electric eels’ discharges can genetically modify the larvae of small fishes.

Using electricity to alter the genetics of microbes is a common lab technique — a technique I’ve used hundreds (thousands?) of times to introduce specific genes into specific bacteria. The technique, known as electroporation, is a biophysical process used to create temporary pores in cell membranes that are large enough to allow DNA or proteins of interest to enter the target cells. The cells go on to heal these pores and to go on living their lives — and expressing this new genetic information.

MORE FOR YOU
A Psychologist Shares 5 Major Reasons Why Marriages Fall Apart
Congratulations, Russian Army: You’ve Invented A Self-Exploding Truck.
Blackpink Has Reportedly Renewed Their Contract To Stay Together

The research team was co-led by Eiichi Hondo, a professor of bioagricultural sciences, and Atsuo Iida, an assistant professor in the same department at Nagoya University. Based on Professor Iida’s knowledge of electroporation and expertise in fishes, the collaborators proposed that when electricity zaps in a body of water, it could also affect nearby organisms (in addition to the resident microbes) to influence them to take up DNA fragments floating in the water. These DNA fragments are known as environmental DNA (more here).

In short, Professor Iida, who is an expert in electric eels, proposed that electroporation is more than just a laboratory process. It could also be a natural process.

“I thought electroporation might happen in nature,” Professor Iida explained. “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.”

Electric eels, Electrophorus sp., are a group of three closely related tropical freshwater fishes found in northern South America. They use electrical impulses to find and court mates and to locate prey. They are known for their ability to stun prey by producing electrical discharges that can reach voltages of up to 860 V — powerful enough to stun an adult human. This ability was known and appreciated by scientists even as far back in 1775, when electric eels were studied to understand the mystery of how they produce electricity. The resulting findings contributed to the invention of the electric battery.

Considering that gene transfer via intense electrical pulses is a well-established technique in genetic engineering, Professor Iida and collaborators proposed that electric eels could potentially function as a living gene transfer mechanism in their aquatic environment.

To test their hypothesis, Professor Iida and collaborators exposed larval laboratory zebrafish to a DNA solution with a genetic marker encoding a green fluorescent protein and exposed the zebrafish larvae to the electric eel’s electric discharge. Then, they introduced an electric eel to the enclosure and prompted it to discharge electricity by biting a feeder (Figure 1). If the zebrafish larvae cells had taken up the DNA, they would glow green (more here).

F I G U R E 1 : EOD exposure from electric eel to zebrafish larvae. (A) The experimental tank used ... [+] to expose the recipient organism to the electric eel’s electric organ discharge (EOD). Within the tank, three carbon rod electrodes are placed: two inputs (colored black and red) and a ground electrode (colored green). (B) An EOD is induced by the electric eel during predatory behavior when it feeds on a goldfish. The cuvette containing zebrafish larvae and a DNA solution is positioned in close proximity to the high-voltage pulses generated by the electric eel. The magenta curve illustrates the electric field produced by the electric eel. (C) The construction of the GFP expression plasmid driven by the Oryzias latipes actb promoter. (D) The photograph displays 7-day post-fertilization (dpf) Danio rerio (zebrafish) larvae that were subjected to microinjection with the indicator plasmid at the one-to-eight cell stages. The plasmid has resulted in robust and widespread GFP fluorescence without apparent developmental abnormalities. Scale bar, 500 µm. (E) An example of a single predatory behavior with the EOD pulses lasting 30 s is shown. The electric eel first bites and swallows the goldfish (indicated by the magenta arrow, 1st bite), followed by another bite at an empty clip (indicated by the blue arrow, 2nd bite). (doi:10.7717/peerj.16596)doi:10.7717/peerj.16596

In fact, 5% of the zebrafish did fluoresce green, providing living evidence that gene transfer had indeed occurred, despite the variability in the pulses produced by the electric eels.

“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,” Professor Iida explained. “Electric eels and other organisms that generate electricity could affect genetic modification in nature.”

This isn’t the first time such a phenomenon has been observed in nature. Lightning, for example, has been found to affect the genetics of nematodes and soil bacteria (ref).

Although this study was conducted in a lab conditions, it relied on live fish, suggesting that electric discharges produced by electric eels could potentially trigger DNA transfer into live larvae in the wild, thereby contributing to those species’ evolutionary trajectories.

But does this, in fact, happen?

Professor Iida and collaborators recognize that they cannot definitively assert that electric discharges do act as a genetic factor in natural settings based solely on these findings, but these studies do suggest that electric discharge-mediated transgenesis could occur in natural habitats — and this series of experiments provides a signpost for future research into the phenomenon.

“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.”

Source:

Shintaro Sakaki, Reo Ito, Hideki Abe, Masato Kinoshita, Eiichi Hondo, and Atsuo Iida (2023). Electric organ discharge from electric eel facilitates DNA transformation into teleost larvae in laboratory conditions, PeerJ 11:e16596 | doi:10.7717/peerj.16596

SHA-256: 9ab94921e06b203a216cb219d873f92ea4083642075e2e0be632939cd42949aa