Biologists and anglers alike have long considered spring and fall run Chinook salmon to be different animals due to variations in fat content, maturity and appearance. But a recent study sheds new light on how Chinook (or king) salmon are genetically quite similar and why this may help the native salmon population in the Klamath River. In a recent study published in the journal Science, HSU Fisheries Biology Professor Andrew Kinziger, HSU graduate student James Hearsey, and their colleagues from NOAA, UC Santa Cruz, and Colorado State University compared billions of DNA bases, the DNA building blocks (e.g., A, T, C, and G), in spring and fall Chinook salmon to see where they differed. To their surprise, they found a minute variation between spring and fall salmon on chromosome 28, in a single small region, known as the Region of Strongest Association or RoSA, that determines when fish migrate upriver.Â