Innovative molecular methods for fish species differentiation

This thesis presents the results of a proof-of-principle study in which a rapid screening method for various market-relevant fish species have been developed. A DNA microarray was established using a set of 100 universal oligonucleotide probes. DNA probe signal patterns were observed to be speciesspecific, enabling species identification of unknown fish samples by comparing the generated DNA probe signal patterns with those of reference specimens. 35 fish species belonging to 14 families were distinguished and three fillet market samples were identified at species level. Snappers are a frequently studied fish family in food science because many mislabeled snapper products are found on the market due to their high morphological and genetic similarities. Especially, the “Red Snapper” (in Germany: L. malabaricus) is particularly prone to mislabeling, and species identification via standard DNA barcoding is difficult due to ambiguous DNA sequences deposited in public nucleotide databases. Therefore, in this thesis the holotype of L. malabaricus (Bloch and Schneider, 1801) and the lectotype of L. erythropterus (Bloch, 1790) were analyzed by nextgeneration sequencing. The mitochondrial DNA sequences of both museum type specimens were found to be 99.77% similar. These results suggest that both investigated type specimens belong to the same species. For the authentication of the snapper species described by both museum type specimens (L. erythropterus), and the snapper species described by public nucleotide database entries annotated as L. malabaricus and L. erythropterus (Lutjanus sp.), an easy, rapid alternative screening method to DNA barcoding was developed. LAMP technology was used to identify both snapper species and two often substituted snapper species (L. argentimaculatus and L. bohar).

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Christian-Albrechts-Universität zu Kiel

Year

2026

Author dc:creator

• Bade, Patrizia Josefine

Contributors dc:contributor

• Brandis, Dirk
• Roth, Olivia

• food fraud
• fish species
• DNA

Repository record source_url

https://macau.uni-kiel.de/receive/macau_mods_00007895

OAI identifier oai:identifier

oai:macau.uni-kiel.de:macau_mods_00007895