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Scientists have pierced fish living in the Pacific trench of Mariani and the trenches in the Indian Ocean. S | Credit: HAN XU et al. (2025) Evolution and genetic adaptation of fish to the deep sea. Cell, Volume 188, Issue 5, 1393 – 1408.E13. Extracted from: https://doi.org/10.1016/j.cell.2025.01.002 (CC from 4.0)
Fish, which survive in extreme deep -sea environments, have developed the same genetic mutation, although they develop separately and at different times, the researchers say.
Scientists have also discovered industrial chemicals in fish and in the ground in Marianic trenchWhich means that human pollutants can reach some of the deepest environments on Earth.
Deep fish have developed unique adaptations to survive extreme pressure, low temperatures and almost complete darkness. These species adapt to extreme conditions through unique skeletal structures, changed circadian rhythms and vision, which is extremely fine for low light, or relies on non-visual senses.
In a new study, Posted on March 6th in Cell MagazineResearchers have analyzed the DNA of 11 fish, including snails, Cusni lies and lizards who live in the Hadali Region area about 19,700 feet (6000 meters) deep and below to understand how they developed under such extreme conditions.
Researchers used submarines with crews and remotely operated vehicles to collect samples from about 3900 to 25 300 feet (1200 to 7 700 m) below the surface of the water, in The Marianic trench In the Pacific and other trenches in the Indian Ocean.
Tracking the evolution of deep-sea fish, the researchers’ analysis revealed that the eight lines of the explored species of fish had entered the deep-sea environment at different times: the earliest probably entered the deep sea at the beginning Scattering period (About 145 million years ago) while others reached it during Paleogen (66 million to 23 million years ago) and some species recently during the Neogen period (23 million to 2.6 million years ago).
Despite the different deadlines for turning the deep sea into their home, all the taught fish living below 9,800 feet (3000 m) show the same type of mutation in the RTF1 gene, which controls how DNA is encoded and expressed. This mutation has occurred at least nine times through deep-sea fish families below 9,800 feet, author of a study OneAn ecologist at the Northwest Polytechnic University, Live Science told an email.
This means that all these fish have developed the same mutation separately as a result of the same environment on the deep sea and not as a result of a shared evolutionary ancestor-to tell how much deep-water conditions they form the biology of these species.
Related: How deep is Mariana’s trench?
“This study shows that deep-sea fish, although they come from many different branches of the fish tree of life, have developed similar genetic adaptations to survive in the harsh environment of the deep ocean-student, dark and high pressure”, “” ” Ricardo BetancourtAn ichthyologist at California University of San Diego, who did not participate in the new study, told Live Science in an email.
This is an example of a convergent evolution in which unrelated species independently develop such features in response to such conditions. “This is a powerful reminder that evolution often uses the same limited set of solutions when it faces similar challenges – in this case, adapting to the extreme conditions of the deep sea,” Betancourt said.
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Expeditions also revealed pollutants produced by people in the trench of Mariana and the Philippine trench. Polychloric biphenyl (PCB) – harmful chemicals Used in electrical equipment and appliances, until they are banned in the 70s – it contaminates the liver tissues of Haldal fish, scientists have found.
High concentrations of PCB and polybromed diffenil essentials (PBDES), Chemicals to slow down the flame Used in consumer products, until they are popular in the early 2000s, they were also found in the nuclei of sediment extracted from over 32,800 feet (10,000 m) deep in Mariana’s trench.
Previous studies also found chemical pollutants in Mariana’s trench as well Microplasty in the deep seaS New discoveries further reveal the impact of human activity even in this ecosystem, which is so far from human life.
Editor’s note: This article was originally published on March 28, 2025.