Admixture history, Czechoslovakian Wolfdog, Demographic history, Genome ancestry, Genome-widedifferentiation, Hybridization, Selection

Background: Genomic methods can provide extraordinary tools to explore the genetic background of wild speciesand domestic breeds, optimize breeding practices, monitor and limit the spread of recessive diseases, anddiscourage illegal crossings. In this study we analysed a panel of 170k Single Nucleotide Polymorphisms with acombination of multivariate, Bayesian and outlier gene approaches to examine the genome-wide diversity andinbreeding levels in a recent wolf x dog cross-breed, the Czechoslovakian Wolfdog, which is becoming increasinglypopular across Europe. Results: Pairwise FST values, multivariate and assignment procedures indicated that the Czechoslovakian Wolfdogwas significantly differentiated from all the other analysed breeds and also well-distinguished from both parentalpopulations (Carpathian wolves and German Shepherds). Coherently with the low number of founders involved inthe breed selection, the individual inbreeding levels calculated from homozygosity regions were relatively high andcomparable with those derived from the pedigree data. In contrast, the coefficient of relatedness betweenindividuals estimated from the pedigrees often underestimated the identity-by-descent scores determined usinggenetic profiles. The timing of the admixture and the effective population size trends estimated from the LDpatterns reflected the documented history of the breed. Ancestry reconstruction methods identified more than 300genes with excess of wolf ancestry compared to random expectations, mainly related to key morphologicalfeatures, and more than 2000 genes with excess of dog ancestry, playing important roles in lipid metabolism, in theregulation of circadian rhythms, in learning and memory processes, and in sociability, such as the COMT gene,which has been described as a candidate gene for the latter trait in dogs. Conclusions: In this study we successfully applied genome-wide procedures to reconstruct the history of theCzechoslovakian Wolfdog, assess indiv