Development of microsatellite markers to identify geographical origin between Korean and Japanese yellowtail, Seriola quinqueradiata

Abstract

This study is about the development of a microsatellite marker for the identification of the origin of domestic and Japanese yellowtail distributed in Korea and the development of a method for determining the origin using the same. Yellowtail accounts for a high proportion of domestic fish production. According to data from the National Statistical Office, yellowtail imports increased from 298 tons in 2015 to 2,240 tons in 2019, an 8-fold increase, and most of the domestic yellowtail imports depend on imports from Japan. While concerns about Japanese fish and the demand for safe aquatic products are increasing, the number of violations of the labeling of origin of aquatic products has increased. The microsatellite marker used in this study is a repeating sequence scattered throughout the genome and is mainly used for comparison analysis of mutations between groups. Therefore, this study suggests the possibility of using microsatellite markers in the import and quarantine process to prevent illegal distribution by developing a method for determining the origin of domestic and Japanese yellowtail products. Genomic DNA was extracted from the fins and muscles by securing a total of 180 yellowtail individuals from 90 domestic and 90 Japanese yellowtail specimens each three times. Whole genomic DNA was treated with restriction enzymes to prepare a GBS library and NGS data was obtained. Sixty nine candidate groups were selected based on the locus that was judged to be able to differentiate between domestic and Japanese products. After PCR, 8 markers were selected through primary and secondary screening to confirm size variation. For the 8 selected markers, the size of the allele was calculated through fragment analysis, and the size of the DNA fragment was determined by performing genotyping. Fragment analysis raw data for 8 markers were analyzed with Cervus 3.0.7, Micro-checker 2.2.3, Arlequin 3.5.2.2, FSTAT 2.9.4, and GenAlEx statistical analysis program. We analyzed the genotype for each group of origin of yellowtail using a combination of newly developed microsatellite markers. It is possible to effectively identify a total of 8 markers and their origin. Among them, based on the FST value, 5 (SqMS32, SqMS33, SqMS36, SqMS43, SqMS45) or 3 (SqMS32, SqMS36, SqMS43) microsatellite marker combinations were used to confirm that efficient origin discrimination was possible. It is expected to be able to effectively discriminate the origin of domestic and Japanese yellowtail by performing PCoA and genotype likelihood matrix analysis through the obtained genotype information. When 8 microsatellite markers were used, it was observed that a colony capable of distinguishing between domestic and Japanese products was formed. Similarly, when using a combination of five (SqMS32, SqMS33, SqMS36, SqMS43, SqMS45) selected by statistical analysis, it was possible to distinguish between domestic and Japanese products. Additional monitoring of yellowtail will allow us to pinpoint the three most effective combinations. Based on the results of this study, it was possible to confirm the possibility of grafting it into the development of on-site diagnosis.