Identidad Con Dna De Rapes (Lophius)

JFS:

Food Chemistry and Toxicology

Genetic Identification of Lophius budegassa and
L. piscatorius by PCR-RFLP Analysis of a
Mitochondrial tRNAGlu/Cytochrome b Segment
A. SANJUAN, J. RAPOSO-G UILLÁN AND A.S. COMESAÑA

Food Chemistry and Toxicology

ABSTRACT: Identification of Lophius budegassa (black-bellied angler) and L. piscatorius (angler) (Lophiiformes)
was carried out on theamplification of a 486 bp tRNAGlu /cytochrome b segment using the polymerase chain
reaction (PCR). Direct DNA sequencing of 6 PCR products was carried out. Six restriction endonucleases (AluI, CfoI,
HaeIII, HinfI, MaeI, and ScrFI) with different species-specific restriction fragment length polymorphism (RFLP) were
selected. Digestions of PCR products from 30 individuals showed no intraspecificpolymorphism. Double digestions
(CfoI and HinfI, and HaeIII and ScrFI) were simpler and more rapid than single digestions. This technique is suitable
for distinguishing tails of both Lophius species.
Keywords: anglerfishes, authentication, cytochrome b, Lophiiformes, PCR-RFLP

Introduction

T

HE IDENTIFICATION OF COMMERCIAL FISH SPECIES
becomes a problem when the distinguishing externalfeatures
of the fish are removed by processing into portions of flesh. The
anglerfishes Lophius budegassa Spinola, 1807 (black-bellied angler)
and L. piscatorius L. 1758 (angler) (Order Lophiiformes, Family
Lophiidae) occur in the northeastern Atlantic (Caruso 1983), where
they are important fishing resources with captures in 1999 of 876
and 53322 metric tons for L. budegassa and L.piscatorius, respectively (FAO 2001). Tails without external characteristics from these species are morphologically indistinguishable (Leiva Moreno 1998).
Fresh, refrigerated, or frozen tails of L. piscatorius are sometimes
labeled and marketed as L. budegassa, owing to the greater popularity and higher consumer demand for this latter species. Moreover, Storelli and Marcotrigiano (2001) have found that23% of L.
budegassa and 62.5% of L. piscatorius samples from the South Adriatic Sea showed mercury concentrations exceeding the tolerable
peak value of 1 mg kg-1 wet wt set by the European Commission.
The mercury concentration can be studied in tails of anglerfishes
and identification of the species can be useful for comparative
purposes. Identification of those products using nonmorphologicalmethods is needed to avoid species substitution and to contribute for the estimate of the quality of these products from a hygienicsanitary standpoint.
Several analytical methods have been developed for fish species authentication, including electrophoretic techniques, highperformance liquid chromatography, and immunoassays (Sotelo
and others 1993; Andrews 1998; Märtlbauer 1998; Etienne andothers 2000, and references therein). Moreover, several of these approaches applied for different species of Lophius allow the identification of them (Lundstrom 1981; Crozier 1988; Grant and Leslie
1993). These methods rely upon the analysis of proteins, many of
which are heat labile, lose their biological activity soon after death,
and are subjet to modification in different cell types. Moreover,the
above methods do not detect all the amino acid differences that
may occur between different proteins (Bartlett and Davidson 1992;
Davidson 1998; Mackie and others 1999; Wolf and others 2000).
Advances in molecular biology techniques have enabled the devel-

2644

JOURNAL OF FOOD SCIENCE—Vol. 67, Nr. 7, 2002

jfsv67n7p2644-2648ms20020036-bw.P65

2644

opment of DNA-based methodsfor the identification of species
origin in food products, as DNA is the same in every cell type of an
individual, its information content is higher than that of proteins,
and it is a remarkably stable molecule (Davidson 1998; Mackie and
others 1999; Wolf and others 2000, and references therein). Most of
these methods are based on amplification of a region of mitochondrial or nuclear DNA...