Genetic identification of nine hake species for detection of commercial fraud.

This study describes the 5S rRNA gene as a simple and reliable one-step PCR-based genetic marker that allows unambiguous identification of Merluccius paradoxus, Merluccius senegalensis, Merluccius australis, Merluccius gayi, Merluccius bilinearis, Merluccius hubbsi, and Macruronus magellanicus. The marker is based on differences in length at the nontranscribed spacer within the 5S rRNA genes and is robust enough for identification of processed products, such as fish fingers and other precooked commercial hake. Further restriction fragment length polymorphism analysis at the mitochondrial cytochrome b gene can distinguish Merluccius merluccius and Merluccius capensis. The application of these markers for routine works such as surveys of quality and labeling of commercial hakes is suggested due to their accuracy, low price, and possible automation for large-scale surveys.