Fishy Phenomenon

​Fishy Phenomenon

By Brandi Argentar

A few years ago, scientists in New York tested fish from local grocery stores and restaurants. They wanted to check if the labels were correct. To everyone’s surprise, they found that over half of the samples were mislabeled — the fish sold as “red snapper” or “tuna” was often a cheaper kind of fish instead.

The scientists used DNA barcoding, a method where they take a small piece of tissue from the food and analyze (study carefully) its DNA. Although the fish pieces appeared identical, their DNA was completely different.

DNA (deoxyribonucleic acid) is the genetic material found in all living things. It carries the instructions for how an organism grows, looks, and functions. Every species — and every person — has its own unique (special, one-of-a-kind) DNA pattern.

DNA barcoding uses gel electrophoresis (a lab test that separates DNA by size) and computers to read the genetic code (the pattern of bases in DNA). Each species has its own DNA “barcode,” just like a product at the store.

By comparing the DNA from the fish to known samples in a database (a collection of information), scientists could identify exactly what species the food came from. This type of testing helps protect consumers, prevent illegal fishing, and ensure that food companies are truthful.

What’s Really on Your Plate? DNA Testing and Food Labels

Open Ended

Why might food companies mislabel fish or other foods?

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How could DNA testing help make food safer or more honest?

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What other products do you think scientists could test with DNA?

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