Stickleback Fish Evolved Rapidly To Living In Freshwater Ponds Following Major Earthquake

Three-spine stickleback fish had to adapt to changing environments on a remarkably short evolutionary timescale, researchers from the University of Oregon (UO) and University of Alaska report in a new study.  

The 1964 Alaskan earthquake – the second highest ever recorded at a 9.2-magnitude – caused a drastic geological uplift that captured many of these saltwater-native fish in newly-formed freshwater ponds on islands in Prince William Sound and the Gulf of Alaska, according to a news release. As a result, the fish experienced genetic changes that manifested in physically: the creatures eyes, body shape, color, bone size and body armor were altered in just a few short decades.

"We've now moved the timescale of the evolution of stickleback fish to decades, and it may even be sooner than that," William Cresko, one of the study researchers from the Institute of Ecology and Evolution at UO, explained in the release. "In some of the populations that we studied we found evidence of changes in fewer than even 10 years. For the field, it indicates that evolutionary change can happen quickly, and this likely has been happening with other organisms as well."

Sticklebacks are small, silver-colored fish found throughout much of the Northern Hemisphere. Studying this evolutionary marvel could help researchers understand the impacts of sudden environmental change on organisms in nature.

"This research perhaps opens a window on how climate change could affect all kinds of species."  Susan L. Bassham, a research associate in Cresko's lab, added in the university's release. "What we've shown here is that organisms - even vertebrates, with long generation times - can respond very fast to environmental change."

For their study, researchers used rapid genome sequencing technology (RAD-seq) to identify genetic changes.

"And this is not just a plastic change, like becoming tan in the sun; the genome itself is being rapidly reshaped," Bassham continued. "Stickleback fish can adapt on this time scale because the species as a whole has evolved, over millions of years, a genetic bag of tricks for invading and surviving in new freshwater habitats. This hidden genetic diversity is always waiting for its chance, in the sea."

This could be good news for flexible species, but further study is required in order to identify those that can readily adapt to climate change.

Their findings were recently published in the Proceedings of the National Academy of Sciences.  

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