In the past, the mainstream impression was that fish living in the deep sea, a "ghost house" where the sun is difficult to reach, do not need eyes. In fact, the blind fish native to Mexico does support this view. Some of them live in the deep sea, some live in the dark and dark caves all year round, although they have no eyes, but the developed sensing organs give them the ability to live in the dark. Blind fish are extremely agile in the water and their ability to prey is very high, as long as they put food, they will immediately find out and quickly swim over to eat.
In the dark, deep sea, the eyes of fish are slowly degenerating as they lose their competitiveness, a discovery that has long been recognized by the public as a textbook. But in recent days, the top academic journal "Science" published an article that is enough to refresh cognition: in the deep sea, there are not only blind people who have lost their vision, but also some strange fish with amazingly good vision!
Over the past few decades, scientists studying the deep sea have found that even in deep-sea waters where sunlight cannot penetrate, there are extremely weak light sources, and further research has found that these light sources come from bacteria, shrimp, and fish that live in the deep sea. Keen researchers were the first to realize that the existence of these light sources was not without reason, so they further hypothesized that there must be some creatures in the deep sea that can detect these light sources.
To test these hypotheses, the scientists conducted large-scale experiments, from the surface of the water to the 2,000-meter deep sea, they collected 101 species of fish living at different depths, and through genome sequencing technology to find genes that can express the RH1 protein (opsin, which can absorb light of different wavelengths and determine the sensitivity of animals).
After analyzing 101 species of fish, the scientists finally found four deep-sea fish species containing more than five RH1 genes. There is also a fish called the silver-finned snapper that contains 38 RH1 genes! The most surprising thing: The researchers found that the RH1 gene function of deep-sea fish is not completely repetitive, and under a series of mutations, some genes encode opsins that are "fine-tuned" to recognize different blue and green lights.
Unlike most deep-sea fish, the silver-winged snapper has a pair of glowing eyes, and a large number of RH1 genes allow it to observe the deep-sea world from its own perspective, they can capture every light source around them, and they have evolved super visual ability.
Because of living in a very stressful environment, improving one's agility is also a survival skill. Abundant visual proteins can make deep-sea fish evolve more perfectly. Because these deep-sea fish are accustomed to the dark life of the deep sea, humans can not take live animals for study, and the judgment of their vision is indeed beyond our expectations. Maybe it is because of this that fish in the deep sea can swim freely in the vast sea.