Electric eels — three species of freshwater fish in the genus Electrophorus — are known for their ability to produce electric organ discharge reaching voltages of up to 860 V. Given that gene transfer via intense electrical pulses is a well-established technique in genetic engineering, biologists from Nagoya University and Kyoto University hypothesized that electric eels could potentially function as a gene transfer mechanism in their aquatic environment.
Electric organ discharge exposure from electric eel to zebrafish larvae. Image credit: Sakaki et al., doi: 10.7717/peerj.16596.
“The electric eel was originally described by Carl Linnaeus in 1766 as Gymnotus electricus, and later revised as Electrophorus electricus in 1864,” said Nagoya University biologist Atsuo Iida and colleagues.
“In 2019, based on both morphological and molecular genetics, they were reclassified into three distinct species: Electrophorus electricus, Electrophorus varii, and Electrophorus voltai.”
“These creatures are renowned for their high-voltage electric organ discharges, which they employ for both predation and defense.”
“Electric eels predominantly hunt and capture prey, particularly fish, using the high-voltage discharges in their natural habitat,” they added.
“In light of this background, we propose the hypothesis that the high-voltage electric organ discharges generated by electric eels during prey capture may have broader effects on neighboring organisms and their habitats in their natural environment.”
To investigate this hypothesis, the authors immersed zebrafish larvae in water containing DNA encoding the green fluorescent protein.
They then exposed larvae to electric eel’s electric organ discharges.
Some larvae exhibited a mosaic expression of green fluorescence, in contrast to the control group without electrical stimulation.
This suggests that electric eel discharges have the potential to function as an electroporator for the transfer of DNA into eukaryotic cells.
“We discovered that 5% of the larvae had markers showing gene transfer,” Dr. Iida said.
“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.”
“Electric eels and other organisms that generate electricity could affect genetic modification in nature.”
“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.”
A paper on the findings was published in the journal PeerJ.
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S. Sakaki et al. 2023. Electric organ discharge from electric eel facilitates DNA transformation into teleost larvae in laboratory conditions. PeerJ 11: e16596; doi: 10.7717/peerj.16596
