Fish began to evolve faster. What is the reason?

The last time fishermen, and then the scientists noticed that some of the fish species began to reach sexual maturity much faster than before. Simultaneously, the average size of individuals has declined significantly. At first it did not attach special significance, but a recent study shows that such changes can be linked to evolutionary processes. And scientists were able to identify mechanisms that affected it.

Why fish started to evolve?

According to the editors of Science Daily, actually, it’s pretty simple: over the last few decades of catching fish is greatly increased and this led to the fact that marine life had to prisposobitsya to this “systematic destruction”.

Most people think of evolution as a very slow process that occurs over several millennia. But evolution can, in fact, happen very quickly. says the study’s lead author, Professor at Cornell University and Nina Overgaard of Terkildsen. Slow growing fish are better to avoid networks, thus having higher chances to transmit their genes to the next generations. Thus, fishing can lead to rapid evolutionary change and development in fish new properties. We see many signs of this effect on the example of the wild fish.

As scientists realized that fish began to evolve

Experts from Cornell University analyzed the data of the experimentconducted in 2002. Six populations of Menidia menidia (live in West Atlanitc), a small commercial fish, the average length is about 15 cm, were subjected to selection in the laboratory. Two populations were removed the largest specimens, and the other two were removed the smallest individuals. In addition prisutstvovala and the control group, where randomly selected several fish of different sizes.

This selection continued for 4 generations and eventually in the last generation body length of the fish in the first group decreased on average by around half. But it has been known for more than 15 years ago. Now scientists, using samples of fish, a fully sequenced genome (that is, in simple words, “spread it into its component parts”), almost 900 individuals and showed a huge change in the composition of DNA. The team found about 200 changes throughout the genome that were consistently changed between populations. They also found stretches of DNA that “turn off” the ability of marine animals to grow. The more was the fish population, the more clearly discernible changes.

A new study, according to scientists, will help to assess human impact on wildlife and to understand how to deal with the consequences, which force animals to evolve around us. The change in one species will inevitably entail changes in the other, and it may harm the entire global ecology.