Study Reveals Evolutionary History of Imperiled Salmon Stocks

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New technologies for analyzing DNA may transform how imperiled species are considered and managed for conservation protection, according to a study published today in the journal Science Advances and led by the University of California, Davis.

These technologies can be applied to a wide range of species around the world — from mushrooms to walruses — but the study focuses on two iconic species of Pacific salmon: steelhead and chinook. While steelhead are a legendary sport fish, chinook are considered the workhorse of the West Coast salmon industry.

New technologies for analyzing DNA may transform how imperiled species are considered and managed for conservation protection, according to a study published today in the journal Science Advances and led by the University of California, Davis.

These technologies can be applied to a wide range of species around the world — from mushrooms to walruses — but the study focuses on two iconic species of Pacific salmon: steelhead and chinook. While steelhead are a legendary sport fish, chinook are considered the workhorse of the West Coast salmon industry.

Spring chinook, summer steelhead can’t re-evolve easily 

Using an inexpensive, efficient DNA analysis method called RAD (restriction-site associated DNA), developed by UC Davis Assistant Professor Mike Miller, the authors found that early migrating salmon populations (called spring chinook and summer steelhead) depend on a single gene. The version of the gene that makes them migrate early evolved only once in each species.

This indicates that the existence of spring chinook and summer steelhead depends on the existence of the right version of the gene, and this genetic variant cannot be expected to easily re-evolve if lost. Spring chinook and summer steelhead are highly prized by fishermen, considered essential by indigenous cultures in the Pacific West, and ecologically important to watersheds.

Read more at University of California - Davis

Photo: Adult spring chinook salmon in California’s Salmon River. (Credit: Michael Bravo)