Applying DNA Techniques to the Identification of the Species of Dressed Toasted Eel Products

Abstract

To differentiate the species of processed eel products, the gene identification of four fresh eel species was first established and the species of eel products collected from markets were investigated. Polymerase Chain Reaction (PCR) and sequence analysis were used to determine the genetic variation in a 362-nucleotide region of the mitochondrial cytochrome b gene in four fresh eels including Anguilla japonica, Anguilla anguilla, Anguilla rostrata, and Muraenesox cinereus. It was found that each eel species had a unique genotype, which was no different among fresh, frozen, and sterilized meats. The restriction enzyme HinfI could differentiate the species of A. japonica and A. rostrata but could not differentiate A. anguilla and M. cinereus. Another restriction enzyme, Sau96 I, was valuable in the differentiation of M. cinereus from the other three species of Anguilla. By applying PCR and restriction enzymes, the species of 12 commercial eel products were identified as A. japonica (9 samples), A. anguilla (2), and A. rostrata (1). This indicated that the sequence and restriction enzyme cutting site analyses were very usable to authenticate species of different processed eel products.

Microsatellite conservation and Bayesian individual assignment in four Anguilla species

“…No sequencing or cloning is needed, and, given a baseline population, assignment scores are extremely high (> 97%). Earlier studies based on reliable PCR-SSCP or RT-PCR techniques required a complete diagnostic marker for each species to classify individuals, and focused mainly on 2 species (Lin et al 2002, Rehbein et al 2002, Hwang et al 2004, Itoi et al 2005 and references therein). The crucial requirements for accurate assignment scores to populations or species are a moderate genetic differentiation (F ST > 5%) and some initial knowledge of genetic variability at each locus, to choose loci less prone to homoplasy (Hansen et al 2001, Estoup et al 2002, Manel et al 2005.…”

“…Eel taxa have been identified using various molecular techniques (Comparini & Rodino 1980, Rehbein et al 2002, Hwang et al 2004, Minegishi et al 2005, and several reliable molecular tests now exist to identify Anguilla spp. simultaneously in processed, historical, or alcohol-preserved samples without sequencing (Lin et al 2002, Itoi et al 2005 and references therein).…”

Authentication of the most important species of freshwater eels by means of FINS

“…To date, several works exist which use DNA methods for eel identiWcation. Among these methods, techniques such as ampliWcation of a partial sequence of DNA by polymerase chain reaction (PCR) followed by direct sequencing of the ampliWed products [8][9][10], restriction fragment length polymorphism analysis [11][12][13][14][15], single nucleotide polymorphism [16,17], real-time PCR analysis [18,19], microsatellite analysis [20], or randomly ampliWed polymorphic DNA analysis method [13,21,22] are very useful. All these works include a low number of eel species.…”

Development of Molecular Tools to Differentiate Sri Lankan Wild Boar (<i>Sus scrofa affinis<i>) Meat from Exotic and Village Pig (<i>Sus scrofa domestica<i>) Meat

“…On the other hand, mtDNA is maternally inherited and only one allele exists in an individual. Therefore, accumulated point mutations can be easily detected in the sequence analysis due to absence of recombination mechanisms facilitating discrimination of closely related species (Hwang et al, 2004). Furthermore, only a small amount of the sample will be adequate for mtDNA analysis due to presence of a large number of mitochondria in each cell (Montielsosa et al, 2000).…”

“…In the case of mtDNA, cytochrome b gene (Hwang et al, 2004), 12S (Fajardo et al, 2008), 16S (Rastogi et al, 2007), 18S (Meyer et al, 1995) ribosomal RNA (rRNA) subunits and displacement loop region (D-loop) (Fajardo et al, 2007) have been used for species identification. Due to maternal inheritance of mtDNA no recombination mechanism exists as in the nuclear DNA to eliminate error once a mutation occurred (Hwang et al, 2004). Thus, accumulation of these point mutations allows discrimination of closely related species (Wolf et al, 1999).…”