Strong Expression of Foreign DNA Fragments Following Intramuscular Injection into the African Catfish, Clarias gariepinus

El Zaeem, Samy Y; Abdallah, Ragaa A; Adam, Hussien A; Hendy, Amany M; Tawfik, Hanaa ZE

doi:10.21608/ejabf.2025.416084.6449

Strong Expression of Foreign DNA Fragments Following Intramuscular Injection into the African Catfish, Clarias gariepinus

Document Type : Original Article

Authors

¹ Animal and Fish Production, Faculty of Agriculture Saba Basha, Alexandria University, Egypt.

² Faculty of Fish and Fisheries Technology, Aswan University, Egypt.

³ Faculty of Fish and Fisheries Technology, Aswan University, Aswan, Egypt.

10.21608/ejabf.2025.416084.6449

Abstract

Gene transfer methods (transgenesis) enable the transfer of traits between organisms to develop new lineages with improved aquaculture performance. Consequently, genetically modified organisms (GMOs) offer potential for genetic enhancements, including faster growth, increased production and efficiency, disease resistance, and broader ecological adaptability. Therefore, this study aimed to investigate the fate of foreign DNA fragments isolated from common carp (Cyprinus carpio) following direct intramuscular injection into African catfish (Clarias gariepinus). Three treatment doses [65μg/ 0.1ml/ fish (T1), 130μg/ 0.1ml/ fish (T2), and 195μg/ 0.1ml/ fish (T3)] were administered via intramuscular injection. The sequence of the glutathione reductase gene (gsr) was used as a molecular marker to validate the DNA transfer approach in the gonads and muscles of African catfish (C. gariepinus). The DNA sequencing results observed a variation in the sequence similarity scores to the sequence of the C. carpio gsr gene in all injected African catfish. Furthermore, to assess the genetic diversity between the same fish before and after intramuscular injection, Inter-Simple Sequence Repeat (ISSR) analysis using five primers revealed a reduction in genetic diversity, particularly in fish receiving the highest dose (195 μg/0.1 ml/fish), as indicated by lower Jaccard’s similarity coefficients (0.56) compared to the other groups. These results, along with the other results from the DNA sequencing, suggested that the same fish, after receiving the exact dose, became genetically modified. In conclusion, this study provides valuable preliminary insights into the direct intramuscular injection of foreign DNA that would be an efficient, time- and cost-effective method for transferring DNA fragments between organisms to create new genetic lines.

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