A new Nature paper on the three-spined stickleback fish "doesn't just spell out the creature's DNA, but also uses it to address some big questions in evolutionary biology," says Not Exactly Rocket Science's Ed Yong. Sticklebacks are important to understanding evolution because they originally lived in the ocean, but have repeatedly evolved to be able to move into streams and lakes and adapt to their new environments and around new predators. "Freshwater sticklebacks around the world have independently picked up the same adaptations, often by tweaking the same genes, and often in just a few generations," Yong says. "This rich history has turned the three-spined stickleback into a supermodel of evolutionary biology. It gives us an unprecedented look at how species adapt to new environments, and whether they do so in predictable ways."
The new study shows 147 genomic regions that differ between marine and freshwater stickleback, and that this area of their genome has been repeatedly changed as the fish have moved around. And an even bigger portion of their genome consists of regulatory genes. "This speaks to a longstanding question in evolutionary science," Yong adds. "Do adaptive changes happen more often in genes themselves, or in the bits of DNA that control them?"