How AFT Can Help Regulators with Food Safety Testing
Every species on the planet, including every species of fish, has a slightly different DNA sequence in its genome. In some areas of the genome, such as in variable repeat regions, the sequence may vary from fish to fish. In other areas, called conserved regions, the DNA is the same for every fish within a species and, but often varies from species to species. Thus, to determine the species of a fish using DNA, one must know the conserved sequences of the species. Sometimes, especially in related fishes, knowledge of multiple conserved regions is necessary in order to properly determine the species of fish.
Several large public databases exist containing DNA sequences. One of the advantages these databases enjoy is that they are inexpensive to use, or free, because the sequences are contributed by various people from around the globe. The principle disadvantage, however, is that anyone can submit any sequence to these databases. Problems arise when a mislabeled (or misidentified) fish is purchased and sequenced and the sequence is added to the database; because mislabeling is so common, most of these public databases contain the common substitutes under each fish species. Thus, using a public database to determine a fish species is not very useful because the data is only as accurate as the least careful person submitting sequences. For this reason, among others, the FDA recommends against the use of public databases.