The genetic status of the Hungarian brown trout populations: exploration of a blind spot on the European map ofSalmo truttastudies

Abstract

BackgroundAnalyses of the control region sequences of European brown trout populations’ mitrochondrial DNA have revealed five main evolutionary lineages (Atlantic, Danubian, Mediterranean, Adriatic, Marble) mostly relating to the main water basins; however, the hybridization between lineages were increasingly reported. Due to the hydrogeography of Hungary, wild populations should theoretically belong to the Danubian lineage, however, this has not been verified by genetic studies.MethodsIn our study multiple molecular marker sets (mitochondrial sequence, microsatellites, PCR-RFLP of nuclear markers and sex marker) were used to investigate the genetic composition and population genetics of the brown trout populations in two broodstocks, six wild streams in Hungary and one Serbian population.ResultsThe admixture of Atlantic and Danubian lineages in these populations, except the Serbian population with pure Danubian origin, was observed by control region sequences of mitochondrial DNA and PCR-RFLP markers in the nuclear genome, and one unpublished Danubian haplotype was found in Hungarian populations. A sex-specific marker revealed equal gender ratio in broodstocks and Kemence stream, whereas in other wild streams the proportion of female individuals were less than 50%. Structure and principal component analyses based on the alleles of microsatellite loci also revealed overlapping populations, however the populations were still significantly different from each other and were mostly in Hardy-Weinberg equilibrium.DiscussionStocking and migration can have a significant genetic impact on trout populations of wild streams, however there are no guidelines or common practices for stocking of small streams in Hungary, thus the genetic background of these populations should be considered when developing conservation actions.

Infirm effect of phylogeny on morphometric features in a cryptic Gobio species complex

“…Therefore, since we used only mitochondrial locus to reveal the phylogenetic features, the presence of hybrids cannot be ruled out in the studied populations. At the same time, the phylogenetic researches have still mostly been done by mitochondrial markers (e.g., Denys et al, 2014Denys et al, , 2021Marić et al, 2017;Ősz et al, 2018;White et al, 2018;Da et al, 2020, etc.). In our study, we were interested in whether the different levels of phylogenetic differences manifest in morphological differences.…”

“…Thus, nowadays the use of dna-based methods are indispensable in the modern taxonomy (Miller, 2007). As a result of molecular studies, the knowledge of intraspecific-variability of several widespread European fish species has been expanded (Šedivá et al, 2008;Bryja et al, 2010;Marić et al, 2012;Palandačić et al, 2015). Moreover, as the results of these investigations the taxonomy of certain wide ranged species have been changed essentially (Denys et al, 2014;Palandačić et al, 2020).…”