Fish DNA Barcoding
Authors:Heather Hill, Michelle Nguyen, Marlen Tagle, Felicia Tang
Mentor:Jo Wu, Professor of Biology, Fullerton College
According to 2012 LA Times article “Fish frequently mislabeled in L.A. restaurants and stores”, fish mislabeling is a common occurrence in California and many parts of the United States. These occurrences pose a threat to public health because consumers may unknowingly be eating unregulated seafood that they may be allergic to or that may carry unwanted diseases from foreign countries. A previous study done by the ocean conservatory organization Oceania revealed that in Southern California alone mislabeling rates were as high as fifty-two percent. This research project was conducted to test the accuracy and identification of fish samples from Orange County restaurants and stores. In this experiment we wanted to determine if recent policies restricting food substitution were being followed in local restaurants and markets. To do this, samples of fish were collected from several locations and then a short section of the mitochondrial DNA was examined to determine how well their DNA matched with the one listed for that species in the national database. We extracted a short section of DNA in the mitochondria called the cytochrome c oxidase 1(CO1) gene, amplified the gene using polymerase chain reaction (PCR), and separated the resulting DNA by gel electrophoresis. DNA sequencing of the PCR-amplified DNA samples was conducted by an external service. After analyzing and comparing the sequence results with the BLAST nucleic acid sequence database, we discovered that a red snapper sushi sample, Lutjanus campechanus, had been mislabeled and was actually Nile tilapia, Oreochromis niloticus. These results demonstrate that fish mislabeling does occur in local Orange County marketplaces and restaurants regardless of the current policies against food mislabeling and substitution. It is evident that more has to be done to increase awareness of this hazard and of other food substitution dilemmas that have been brought up in the recent years.