The toothy monster from the depths, which lures prey with bright light directly into its mouth, recently posed a new mystery to scientists. Science already knew that bioluminescent bacteria were the source of light in the angler fish's "lamp". However, the recent sequencing of their genome has made biologists wonder - what role does their host fish actually play in the life of bacteria?
Catching an angler fish at great depths is not easy, there has always been a shortage of materials for study, and scientists were content with generalizations. There is nothing surprising in bioluminescence, the phenomenon of symbiosis is well known, so it is logical to assume that bacteria help the angler to lure prey, and that in gratitude feeds them. This duo was formed about 100 million years ago and reached perfection.
However, after studying the DNA of bacteria from anglers from different regions of the oceans, scientists were amazed to discover two new facts. First, it turned out to be different microorganisms, they have only the effect of bioluminescence in common. Second, the genome of bacteria from fish was 50% poorer than that of their close relatives. And he had signs of degeneration, pseudogenes, which should soon atrophy and disappear.
We are talking about important parts of the genome, losing which, the bacterium lowers its chances of finding food and surviving. But there is no problem - everything it needs is provided by the body of the angler fish. The details of the process in different studied individuals differ so much that a new theory arose: fish influences the evolution of bacteria. It makes the microbes degrade and become dependent on it, and when they completely degenerate, it changes the "stuffing" of the light bulb and starts the process anew. So far, this is only a theory, but it excites the minds of scientists.