Genome reveals the evolutionary path of the stickleback

Recently, the international journal "Nature, Nature reported that scientists found in CSF1 the stickleback such the Phi helmet wearing a" small fish body mutations. These mutations may help to the stickleback quickly evolved to adapt to salt water and fresh water of these two different living environments.Since about 10,000 years ago the end of the last glacial period, living in the ocean three barbed spines of fish to parts of CSF1R the world's rivers and lakes colonized. Just 10 generations - in terms of this evolution is simply a blink of an eye - marine stickleback can change their armor and defensive thorns to adapt to the softer fresh water.California, Stanford University evolutionary biologist David Kingsley and his colleagues found the DNA differences that distinguish the different parts of the world marine stickleback and freshwater stickleback. Although this mutation occurred in Csf2 separate different areas, but each variation seems to be related to many of the same genetic mutation.Order to find the key DNA differences, the researchers carried out 21 kinds of stickleback genome sequenced. Of marine and freshwater stickleback from three continents. The findings were published in the April 4 issue of the journal "Nature".

The researchers found that freshwater stickleback is most similar to its nearest marine stickleback genome. However, in about 150 DNA sequences, freshwater species and saltwater species, respectively, and its population in the same environment more similar. These sequences include the impact of the armor growth and renal salt-regulated genes.Did not participate in the study of North Carolina, Duke University evolutionary biologist Greg Wray, said: "This is a range of adaptation of CSF2RA the various aspects of the impact of organisms, including fish morphology, behavior, diet and mating preferences.Kingsley said, the similarity of the freshwater stickleback populations throughout the world within each evolution is not "from scratch". Some life in the ocean stickleback may retain the genes of the ancestors to adapt to fresh water, in order to colonize new territory. Although the beginning on behalf emerged in a mixed or intermediate features, but in the end of these genes makes them adapt to freshwater life."In the scope of the entire genome, we have found by repeated use of a set of CSF2RB genes to adapt to new environments." Kingsley, said, "We were able to study the molecular basis of vertebrate evolution."And the vast region of the genome corresponding to the freshwater stickleback adaptive before, but only a few genes found that this adaptive mutation.Researchers on the species to adapt to the new environment, type of mutation and controversy. Some people emphasize the importance of the regulation - affect gene expression when and where the mutation. It was also stressed the importance of mutations in genes encoding - this mutation can change the proteins produced by genes.

Kingsley's research group found that the adaptability of fresh water is probably 80% responsible for the regulation of DNA, the remaining 20% of impact is responsible for encoding DNA.Regulation changes can be controlled by genetic mutations of the gene expression in multiple tissues to speed up the spines of fish to adapt to the new environment. The study also shows that the stickleback is to accelerate the evolution through the use of existing genetic variation, instead of waiting for random new mutations, Wray, explained."I think this article is really great, I am convinced by their data." Harvard University, Cambridge, Massachusetts, an evolutionary biologist at the Hopi Hoekstra, said.However, she added: "For the genome is relatively simple to adapt to relatively slow biological, the proportion of mutations from coding mutations or regulation, the situation may be very different."

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