How Electric Fish Were Able to Evolve Electric Organs
DannyB writes:
Phys.org
How electric fish were able to evolve electric organs
Electric organs help electric fish, such as the electric eel, do all sorts of amazing things: They send and receive signals that are akin to bird songs, helping them to recognize other electric fish by species, sex and even individual. A new study in Science Advances explains how small genetic changes enabled electric fish to evolve electric organs. The finding might also help scientists pinpoint the genetic mutations behind some human diseases.
Evolution took advantage of a quirk of fish genetics to develop electric organs. All fish have duplicate versions of the same gene that produces tiny muscle motors, called sodium channels. To evolve electric organs, electric fish turned off one duplicate of the sodium channel gene in muscles and turned it on in other cells. The tiny motors that typically make muscles contract were repurposed to generate electric signals, and voila! A new organ with some astonishing capabilities was born.
[....] researchers from UT Austin and Michigan State University describe discovering a short section of this sodium channel gene-about 20 letters long-that controls whether the gene is expressed in any given cell. They confirmed that in electric fish, this control region is either altered or entirely missing. And that's why one of the two sodium channel genes is turned off in the muscles of electric fish.
[....] "This control region is in most vertebrates, including humans," Zakon said. "So, the next step in terms of human health would be to examine this region in databases of human genes to see how much variation there is in normal people and whether some deletions or mutations in this region could lead to a lowered expression of sodium channels, which might result in disease."
[....] Zakon said the sodium channel gene had to be turned off in muscle before an electric organ could evolve.
"If they turned on the gene in both muscle and the electric organ, then all the new stuff that was happening to the sodium channels in the electric organ would also be occurring in the muscle," Zakon said. "So, it was important to isolate the expression of the gene to the electric organ, where it could evolve without harming muscle."
[....] "If you rewound the tape of life and hit play, would it play back the same way or would it find new ways forward? Would evolution work the same way over and over again?" said Gallant, who breeds the electric fish from South America that were used in part of the study.
It is shocking that electric organs are not only for musicians.
More information: Sarah LaPotin et al, Divergent cis-regulatory evolution underlies the convergent loss of sodium channel expression in electric fish, Science Advances (2022). DOI: 10.1126/sciadv.abm2970 or www.science.org/doi/10.1126/sciadv.abm2970
Journal information: Science Advances
Read more of this story at SoylentNews.