Predictable evolution trumps randomness of mutations
Although mutations, the driver of evolution, occur at random, a study of the bacterium Escherichia coli reveals that nature often finds the same solution to the same problem again and again.
Over time, random mutations enable organisms to adapt and diversify, often when geographically separated groups of the same species grow better suited to their local environment and less like members of the other group.
But that’s not the only way that genetic diversity can arise. Researchers have reported cases of cichlid fish, palm trees and finches adapting to different ecological niches and splitting into different species despite living in the same place1–3. In 2008, evolutionary biologist Michael Doebeli of the University of British Columbia (UBC) in Vancouver and colleagues reported that E. coli bacteria can also diversify while sharing a test tube4.
In that study, they fed easy-to-digest glucose and a harder-to-stomach acetate to homogeneous populations of the bacteria, and let the bacteria chomp away. E. coli can switch between the two foods, but the team found that in each test tube two groups emerged, specialized in consuming either glucose or acetate. What they did not know was which genetic path each group took to achieve its specialisation.
Scientific American also picked up the story [html]