After the last ice age, when glaciers melted and fresh water streamed across land masses, many animals adapted to new habitats. HHMI investigator David Kingsley and a team of international scientists have followed a fish—the three-spine stickleback—to determine what genetic changes allowed it to thrive in new environments in North America, Europe, and Asia.
Kingsley’s team at Stanford University School of Medicine and scientists from the Broad Institute of MIT and Harvard collaborated with international scientists to uncover the complete genome sequences of 21 members of the stickleback family collected from around the world. As described in Nature, on April 5, 2012, the scientists looked for DNA sequences that had changed as the fish adapted.
|Kingsley discusses how sticklebacks colonized lakes, how regulatory gene switches work, and how he got into science.|
Amazingly, 147 regions in the genome were consistently altered across the 21 sticklebacks. The genetic regions are associated with metabolism, developmental processes, behavior, and body armor formation, identifying a suite of changes that enabled the formerly saltwater fish to survive in fresh water. More than 80 percent of the changes were found in regulatory sequences rather than protein-coding regions, helping to answer a long-standing debate about the relative importance of regulatory and coding changes during adaptive evolution. By studying the diverse stickleback genome, Kingsley says, “we can find the key genes that control evolutionary change.”