How fast can vertebrates adapt to new environments? In a recent publication in PNAS, the Cresko lab and collaborators from University of Alaska Anchorage presented evidence that, in just five decades, some freshwater populations of stickleback fish have diverged morphologically and genomically from their immediate marine relatives. And this divergence is nearly as great as has been measured in freshwater populations that were founded by marine fish more than 10,000 years ago. The study took advantage of natural freshwater populations of fish that could not have existed before the 1964 Great Alaska Earthquake, which dramatically heaved up sea floor around marine islands and created new freshwater ponds. The researchers used RAD-seq genotyping of over 1000 fish to analyze genetic structure and conclude that rapid adaptation happened several times independently among the more than 20 populations studied. The findings have significance for understanding how fast even species with long generation times can adapt in a changing environment. Read more at this article on “Around the O”.