Endemic gene pools have been severely endangered by human-mediated hybridization, which is posing new challenges in the conservation of several vertebrate species. The endangered European wildcat is an example of this problem, as several natural populations are suffering introgression of genes from the domestic cat. The implementation of molecular methods for detecting hybridization is crucial for supporting appropriate conservation programs on the wildcat. In this study, genetic variation at 158 single-nucleotide polymorphisms (SNPs) was analyzed in 139 domestic cats, 130 putative European wildcats and 5 captive-bred hybrids (N=274). These SNPs were variable both in wild (HE=0.107) and domestic cats (HE=0.340). Although we did not find any SNP that was private in any population, 22 SNPs were monomorphic in wildcats and pairwise FCT values revealed marked differences between domestic and wildcats, with the most divergent 35 loci providing an average FCT>0.74. The power of all the loci to accurately identify admixture events and discriminate the different hybrid categories was evaluated. Results from simulated and real genotypes show that the 158 SNPs provide successful estimates of admixture, with 100% hybrid individuals (two to three generations in the past) being correctly identified in STRUCTURE and over 92% using the NEWHYBRIDS’ algorithm. None of the unclassified cats were wrongly allocated to another hybrid class. Thirty-five SNPs, showing the highest FCT values, provided the most parsimonious panel for robust inferences of parental and first generations of admixed ancestries. This approach may be used to further reconstruct the evolution of wildcat populations and, hopefully, to develop sound conservation guidelines for its legal protection in Europe.

SNPs_publication_ATCGfile 1: 'SNPs_publication_ATCG': this file contains the raw SNPs database in GenAlEx format for two sets of samples (sheets 1 and 2): sheet 1: SNPs data for all 274 cat samples used in the analyses (139 domestic cats - FCA; 130 putative European wildcats - FSI; 5 known hybrids FCA x FSI), characterised by 158 loci; sheet 2: SNPs data for 226 cat samples (139 domestic cats - FCA; 82 European wildcats - FSI; 5 known hybrids FCA x FSI), characterised by 158 loci. This sample set was created to exclude possible hybrids from the representatives of European wildcats. These files can be converted to other formats using GenAlEx.SNPs_publication_012File 2: This file contains the same SNPs datasets as in file 1, but in numerical format as required by GenAlEx for data analysis. These files can be converted to other formats using GenAlEx