Filogeografski status i genetička struktura populacija potočne pastrmke (Salmo cf. trutta) Đerdapa i Timočke krajine

Abstract

Kontrolna regija mitohondrijske DNK pokazala se kao odličan filogeografski marker kad je kompleks potočne pastrmke (Salmo cf. trutta) u pitanju. Krajem 20. veka ustanovljeno je pet osnovnih filogeografskih linija (haplogrupa) potočne pastrmke: dunavska, atlanska, mediteranska, jadranska i marmoratus koje uglavnom korespondiraju sa odgovarajućim slivovima. Analizirane jedinke na području Srbije nosile su haplotipove dunavske, atlanske i jadranske haplogrupe. Najdominantniji haplotip u slivu Crnog Timoka i rekama desne obale Dunava u Đerdapskom regionu pripadao je dunavskoj liniji i opisan je pod imenom Da23c (ACCN KC630984). Obzirom da je ovaj haplotip zasada otkriven samo u ovoj oblasti i to sa velikom učestalošću smatra se autohtonim za ovu regiju. U okviru Đerdapskog regiona uočen je i haplotip Da1, ali samo u Rečkoj reci u njenom desnom delu iznad nepremostive prepreke, vodopada visine 10 m. Kao pleziomorfni u odnosu na haplotip Da23c i široko rasprostranjen na ovom delu Balkanskog poluostrva postoji velika verovatnoća da je i on autohton za ovo područje, međutim nije isključena ni mogućnost da je unesen poribljavanjem. U okviru sliva Crnog Timoka osim autohtonog haplotipa Da23c otkriven je i Da2, koji je najverovatnije alohton. U prilog tome govore činjenice o rasprostranjenju haplotipova na zapadnom Balkanu, kao i podaci o korišćenju jedinki ovog haplotipa za poribljavanje i gajenje u Austrougarskoj, a kasnije u celoj Evropi i Srbiji. Osim dunavske u okviru šireg područja Đerdapa otkriveno je i prisustvo atlanske linije u rekama Brnjica, Dobrinjska, Porečka i Vratna, a samo u poslednjoj jedinke atlanskog haplotipa koegzistiraju sa pastrmkama koje nose autohtoni haplotip, Da23c. Atlanski haplotip ne smatra se autohtonim za Balkansko poluostrvo, pa je najverovatnije u reku Vratnu dospeo poribljavanjem, a analize jedarnog gena, laktat dehidrogenaze, pokazale su da se ove jedinke međusobno ukrštaju. Programske analize podataka osam mikrosatelitskih lokusa ukazale su na postojanje pet izdvojenih populacija u regionu severoistočne Srbije: sliv Crnog Timoka, reka Kožica, reka Rečka, reke Vratna i Zamna zajedno i reke Mala Boljetinska i Zlatica zajedno, što ukazuje na verovatnu komunikaciju i protok gena između ovih populacija. Mere upravljanja ovim ribolovnim područjima isključuju poribljavanje, jer trenutno ne postoji veštački mrest gde se koristi genetički materijal autohton za ovu oblast...

Control Region of mitohondrial DNA is a good phylogeographic marker for brown trout species complex (Salmo cf. trutta). Five main brown trout phylogeographic lineages (haplogroups) that mostly correspond to the particular basins have been established at the end of 20th century: Danubian, Atlantic, Mediteranean, Adriatic and marmoratus. Individuals from Serbia held haplotypes of Danubian, Adriatic and Atlantic haplogroups. Prevailing haplotype in the River Crni Timok drainage area and in the right tributaries of the River Danube from Đerdap region is Da23c (ACCN KC630984) of Danubian haplogroup. This haplotype is considered indigenous there since it has been found only in this area and with a great frequency. Another haplotype also detected in the Đerdap region is Da1, but only in the River Rečka, in its right fork above the 10 m high waterfall, which is an impassable obstacle for upstream dispersal of brown trout from downstream section. Considering its plesiomorphic character compared to haplotype Da23c and its wide distribution in this part of Balkan Peninsula, there is a high probability that it is indigenous for this region, as well. However, the possibility that it has been imported by stocking activities cannot be excluded. In addition to the indigenous haplotype Da23c, the haplotype Da2 was also detected in the Crni Timok drainage area, probably as an allochthonous one. This was supported by haplotype distribution in Western Balkans, as well as by history of stocking and breeding with the Da2 haplotype in Austria-Hungary and later, both in middle and southeastern Europe, including Serbia. Individuals of the Atlantic haplogroup were detected in rivers Brnjica, Dobrinjska, Porečka and Vratna of the broader Đerdap area. Only in the last river these individuals coexist in sympatry with brown trout of indigenous Da23c haplotype. Since Atlantic haplotype was not considered indigenous for Balkan Peninsula, it has been probably introduced there by stocking. Analysis of nuclear gene lactate dehydrogenase showed that individuals of two lineages occurring in sympatry interbreed. Data software analyzes of eight microsatellite loci revealed the existence of five separated populations in Eastern Serbia: (1) Crni Timok drainage area, (2) River Kožica, (3) River Rečka, (4) Rivers Vratna and Zamna, and (5) River Mala Boljetinska and River Zlatica, indicating a potential communication and gene flow between these populations...