The Atlantic cod (source: U.S. National Oceanic and Atmospheric Administration)
The DNA of Atlantic cod is full of surprises for immunologists and evolutionary scholars. A complete map of the genome of these fish, it indicates that they have a unique immune system, without a decisive weapon to fend off viruses and bacteria, yet equally effective. The study, published in Nature and led the Norwegian University of Oslo, open important questions on the evolution of vertebrates and can be crucial to understand the issues important to the breeding of this fish reserve.
The researchers found that cod is absent in the DNA of the so-called Major histocompatibility complex II (MHC II), a real kit for the immune system in many vertebrates. Kjetill Jakobsen and his group have observed that despite this lack of cod is still able to protect themselves against pathogens expressing a greater number of Mhc genes of the group I.
This explains how the immune system of Atlantic cod have evolved compensatory mechanisms, it is an observation that calls into question the fundamental assumptions about the evolution of defense mechanisms of vertebrates.
Cod is one of the most caught fish in the world but the great fishing that is subject to exhaustion is leading stocks, so as to be almost completely disappeared from the coasts of Canada, the North Sea and the Baltic.