During last fall's salmon run, researchers collected Coho salmon DNA from the air beside Issaquah Creek, near the Issaquah Salmon Hatchery in Washington. A researcher had the idea while hiking, so the team set air filters at several sites beside the stream. The filters caught Coho DNA even 10 to 12 feet from the river.
For sampling, filters were left for 24 hours on six days between August and October. The team tested four filter types each time, including three vertical filters and an open 2-liter tub of deionized water to catch falling particles. In the lab they washed the samples and measured DNA with a Coho-specific tag using polymerase chain reaction, a DNA test. The results show air and water eDNA can be linked to salmon movement.
Difficult words
- hatchery — place where fish are born and raised
- filter — device that removes particles from air or waterair filters, filters, filter types, vertical filters
- sampling — act of taking small material for testing
- polymerase chain reaction — laboratory method to make many DNA copies
- DNA — molecule that carries genetic information
- movement — change of position or place over time
- stream — small river where water flows
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Do you think collecting DNA from the air is useful? Why?
- Have you ever hiked near a river? What did you notice?
- Would you like to work in a lab that tests DNA? Why or why not?
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