In order to elucidate genetic composition of European grayling (Thymallus thymallus) populations in the Western Balkans, the partial mitochondrial DNA (mtDNA) control region was sequenced and 12 microsatellite loci genotyped in 14 populations originating from tributaries of the Adriatic and Danube drainages. Eleven mtDNA haplotypes were found, one confined to the Adriatic clade, one to the Alpine group and the rest to the "Balkan" grayling phylogenetic clade. Haplotypes from the Balkan clade were confined to the Danube drainage and constituted two groups:northern group with haplotypes found in the Slovenian part of the Danube drainage, and southern group, consisting from Bosnia-Herzegovina and Montenegro. Substantial genetic distance between northern and southern groups of haplotypes (0.75-1.8%) and well supported divisions within the northern group indicate very structured grayling population within the studied Danube basin that most probably did not evolve due to variance but rather as a consequence of multiple conolization waves that might have occured during the Pleistocene. Furtermore, genetic distance of - 4% between Adriatic and Danube populations' haplotypes, suggest that their separation occured in mid-Pliocene. These findings imply a complex colonization pattern of the Western Balkans drainages. Microsatellite data also confirm high genetic diversity in Western Balkans populations of grayling (on average 7.5 alleles per microsatellite locus and Hexp 0.58). Limited stocking activities were detected based on microsatellites and mtDNA data. Regarding current knowledge of grayling phylogeography appropriate management strategies were proposed to preserve unique, autchthonous grayling populations in Western Balkan.
COBISS.SI-ID: 3027080
The structure and diversity of grayling (Thymallus thymallus) populations have been well studied in most of its native habitat; however the southernmost populations of the Balkan Peninsula remain largely unexplored. The purpose of this study was to access the genetic diversity of Serbian grayling populations, detect the impact of stocking and provide guidelines for conservation and management. Eighty grayling individuals were collected from four rivers (Ibar, Lim, Drina and Rzav). The mitochondrial DNA control region (CR; 595 bp of the 3'end and 74 bp of flanking tRNA) and the ATP6 gene (630 bp fragment) were sequenced for 20 individuals (five from each locality). In addition, all individuals were genotyped with 12 microsatellite loci. The diversity and structure of the populations as well as the recent and ancient population declines were studied using specialized software. We detected three new haplotypes in the mtDNA CR and four haplotypes in the ATP6 gene of which three had not been described before. Previously, one CR haplotype and two ATP6 gene haplotypes had been identified as allochthonous, originating from Slovenia. Reconstruction of phylogenetic relations plased the remaining two CR haplotypes from the River Danube drainage of Serbia into a new clade, which is related to the previously described sister Slovenian clade. These two clades a new Balkan clade. Microsatellite marker analysis showed that all four populations are genetically distinct from each other without any sign of intrapopulation structure, although stocking of the most diverse population (Drina River) was confirmed by mtDNA analysis. recent and historical population declines of Serbian grayling do not differ from those of other European populations. Our study shows that (1) the Ibar, Lim and Drina Rivers grayling populations are genetically distinct from populations outside of Serbia and thus should be managed as native populations in spite of some introgression in the Drina River population and (2) the Rzav River population is not appropritae for further atocking activities since it originates from stocked Slovenian grayling. However, the Rzav River population does not represent an immediate danger to other populations because it is physically isolated from these.
COBISS.SI-ID: 2821000