Though separated by a world of ocean, and unrelated to each other, two fish groups – one in the Arctic, the other in the Antarctic – share a surprising survival strategy: They both have evolved the ability to produce the same special brand of antifreeze protein in their tissues. A new study describes in molecular detail how the Arctic fishes built the gene for their antifreeze from tiny fragments of noncoding DNA, regions once considered “junk DNA.”

The findings are reported in the Proceedings of the National Academy of Sciences.