Characterization of the genetic structure of the brown trout (Salmo trutta) from "Braduljica" fish farm, Serbia

Abstract

Due to the ecological concerns and preservation of genetic resources, the characterization of genetic structure of the brown trout (Salmo trutta) was carried out on the "Braduljica" fish farm. DNA was isolated from fin clips of 10 individuals, and after that molecular PCR-RFLP methods were used for distinguishing between Atlantic and Danubian lineages based on control region of the mitochondrial DNA (CR mtDNA) and lactate dehydrogenase gene of the nuclear DNA (LDH nDNA). Based on phenotypic characteristics it was estimated that out of 10 individuals included in this study five belonged to the allochtonous Atlantic lineage and remaining five belonged to the native Danubian lineage of brown trout. However, results of molecular analyses showed a high percentage of allochthonous genes among the individuals, which confirms the hybridization between these two lineages. Also, the results showed that the selection based on the phenotype is not adequate. In order to continue with proper broodstock management, it is necessary to eliminate allochtonous individuals of the Atlantic lineage from the broodstock.

U cilju zaštite ţivotne sredine i genetiĉkih resursa potoĉne pastrmke (Salmo trutta) u radu je ispitivana genetiĉka struktura ove vrste na ribnjaku ―Braduljica‖ u blizini Ivanjice. DNK je izolovana iz odseĉaka peraja 10 jedinki, a nakon toga molekularne PCR-RFLP metode su korišćene za razlikovanje izmeĊu atlantske i dunavske linije na bazi kontrolnog regiona mitohondrijalne DNK (KR mtDNK) i jedarnog gena za laktat dehidrogenazu (LDH nDNK). Na osnovu fenotipskih karakteristika procenjeno je da je pet jedinki pripadalo alohtonoj atlantskoj liniji, a preostalih pet autohtonoj dunavskoj liniji potoĉne pastrmke. MeĊutim, rezultati molekularnih analiza pokazali su prisustvo visokog procenta alohtonih gena u analiziranom uzorku, što potvrĊuje hibridizaciju izmeĊu ove dve linije. TakoĊe, rezultati ukazuju na to da selekcija na osnovu fenotipa nije adekvatna. Kako bi ribnjak nastavio da se bavi gajenjem potoĉne pastrmke za potrebe poribljavanja okolnih reka, neophodno je da se eliminišu jedinke atlantske linije iz matiĉnog fonda.