Fish began to evolve rapidly. What is the reason?
Recently, fishermen, and then the scientists noticed that some species of fish began to reach sexual maturity much faster than before. At the same time the average size of the individuals decreased significantly. At first, it did not attach much importance, but a recent study shows that such changes may be related to evolutionary processes. And the scientists were able to identify the mechanisms that affect it.
Why the fish began to evolve?
According to the edition of the publication Science Daily, in fact, it's pretty trivial: in the last few decades, catching of commercial fish species has increased significantly, and this has led to the fact that marine life had somehow Adapts to this "systematic destruction".
Most people think of evolution as a very slow process that takes place over several millennia. But evolution is, in fact, happen very quickly. - says the study's lead author, Professor Cornell University Nina Overgaard-Terkildsen. Slow-growing fish would be better to avoid chains, thus having a better chance to pass on their genes to the next generation. Thus, the fishing can lead to rapid evolutionary change and development in fish of new properties. We see many signs of this effect on the example of wild fish.
As the scientists realized that the fish began to evolve
Experts from Cornell University analyzed data from an experiment conducted in 2002. Six populations Menidia menidia (inhabit Western Atlanitke), small food fishes, the average length of which is about 15 centimeters, were subjected to in vitro selection. The two populations were removed most large individuals, while in the other two the smallest specimens were removed. In addition, the control group were present and where randomly selected a few fish of different sizes.
See also: What is the smallest shark in the world.
The selection lasted for 4 generations, and as a result in the last generation of fish body length in the first group decreased on average by about half. But it has been known for more than 15 years ago. Now scientists are using fish specimens, fully sequenced genome (ie, simple words, "spread it into its component parts") of almost 900 individuals and found huge changes in the DNA. The team found about 200 changes throughout the genome that are consistently varied between populations. They also found the DNA regions that are "turned off" the ability of marine animals to grow. The larger fish populations are, the more accurately track changes.
A new study, according to scientists, will help to assess the human impact on wildlife and understand how to deal with the consequences, which cause the animals around us evolve. After the change of some species invariably entail a change and others, and this can harm the ecology of the entire world.
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