İnvestigation of disease resistant gene region and genetic characterization of Luciobarbus esocinus species living in Keban Dam Lake

In this master thesis, Luciobarbus esocinus (Heckel, 1843) species living in Keban Dam Lake; It is known that it lives endemic in the Euphrates and Tigris rivers and is one of the important aquatic economic resources especially for the Keban Dam Lake and its surroundings. Conservation of populations of Luciobarbus esocinus, proper fisheries management and genetic characterization studies for future culture studies are of great importance for this species as well as for any other species. During the study phase, 29 Luciobarbus esocinus specimens were obtained by trying to collect from 3 different locations determined in Keban Dam Lake. Gene expressions were determined in the MH-IA and MH-IB gene regions to investigate the resistance to the disease by RNA isolation, cDNA synthesis and Real time PCR applications from muscle tissues taken from these samples. As a result of the study; it was observed that all samples gave positive results as a result of Real-Time PCR using primers designed specific to the β-actin gene for molecular identification of Luciobarbus esocinus species. In addition, in the Real-Time PCR analysis performed using cDNAs obtained from RNAs isolated from muscle tissues in order to determine the disease resistance gene expression levels, expression values close to the control were observed in the fish taken from Region 1, while down-regulation in MH-IA gene and up-regulation in MH-IB gene were observed in the samples taken from Region 2. In the samples taken from the 3rd region, upregulation was observed in both MH-IA and MH-IB genes. In line with these results, it was observed that the expression levels of disease resistance genes in Luciobarbus esocinus species living along the same water source gave close results in the samples taken from 3 regions considering the reasons such as similar water quality criteria, presence of similar disease agents in the same water source and exposure of the host to the same species. The results of this study carried out in Keban reservoir need to be developed in future studies and new studies are needed in which all resistance mechanisms will be examined with different fish species and genome-specific studies.