Genetic distinction of wildcat (Felis silvestris) populations in Europe, and hybridization with domestic cats in Hungary

Abstract

The genetic integrity and evolutionary persistence of declining wildcat populations are threatened by crossbreeding with widespread free-living domestic cats. Here we use allelic variation at 12 microsatellite loci to describe genetic variation in 336 cats sampled from nine European countries. Cats were identified as European wildcats (Felis silvestris silvestris), Sardinian wildcats (F. s. libyca) and domestic cats (F. s. catus), according to phenotypic traits, geographical locations and independently of any genetic information. Genetic variability was significantly partitioned among taxonomic groups (FST = 0.11; RST = 0.41; P < 0.001) and sampling locations (FST = 0.07; RST = 0.06; P < 0.001), suggesting that wild and domestic cats are subdivided into distinct gene pools in Europe. Multivariate and Bayesian clustering of individual genotypes also showed evidence of distinct cat groups, congruent with current taxonomy, and suggesting geographical population structuring. Admixture analyses identified cryptic hybrids among wildcats in Portugal, Italy and Bulgaria, and evidenced instances of extensive hybridization between wild and domestic cats sampled in Hungary. Cats in Hungary include a composite assemblage of variable phenotypes and genotypes, which, as previously documented in Scotland, might originate from long lasting hybridization and introgression. A number of historical, demographic and ecological conditions can lead to extensive crossbreeding between wild and domestic cats, thus threatening the genetic integrity of wildcat populations in Europe.

European wildcat populations are subdivided into five main biogeographic groups: consequences of Pleistocene climate changes or recent anthropogenic fragmentation?

“…At threshold q i  = 0.80, we identified 77 admixed samples in the European wildcat populations, including one misclassified domestic cat, seven captive‐bred hybrids and ten previously identified hybrids (Pierpaoli et al. 2003; Lecis et al. 2006).…”

“…Wild‐living cats in Scotland and Hungary are deeply introgressed, making difficult the identification of pure parental cats, as previously described using smaller STR panels and cat sample sizes (Pierpaoli et al. 2003; Lecis et al. 2006), or using SNPs (Oliveira et al.…”

“…This partition confirms and strengthens findings previously reported by Pierpaoli et al. (2003). These authors described a main genetic subdivision among the European wildcat populations distributed in southern and central Europe and separated the wildcats in central Germany from all the other European populations.…”

“…Molecular and morphological identifications concordantly evidenced the consequences of genetic admixture, which makes it difficult to ascertain whether any pure wildcat is still surviving in these two countries (e.g., Pierpaoli et al. 2003; Kitchener et al. 2005).…”

“…The other ten wild‐living hybrids were genetically identified in other studies (Pierpaoli et al. 2003; Lecis et al. 2006; Mattucci et al.…”