Genetic diversity and introgression in the Scottish wildcat

This paper describes a genetic analysis of wild-living cats in Scotland. Sa mples from 230 wild-living Scottish cats (including 13 museum skins) and 74 house cats from England and Scotland were surveyed for nine microsatellite loci. Pelage characteristics of the wild-living cats were recorded, and th e cats were then grouped into five separate categories depending on the deg ree to which they conformed to the characteristics attributed to Felis silv estris Schreber, 1775. Allele frequency differences between the morphologic al groups are greater than those among the three house cat samples. Analysi s of genetic distances suggests that more of the differences between indivi duals can be explained by pelage than geographical proximity, and that pela ge and geographical location are not confounded. Ordination of the genetic distances suggests two main groups of wild-living cats, with intermediates, and one group is genetically very similar to the house cats, while the oth er group contains all cats taxonomically identified as wildcat based on mor phology. A genetic mixture analysis gives similar results to the ordination , but also suggests that the genotypes of a substantial number of cats in t he wildcat group are drawn from a gene pool with genotypes in approximately equilibrium proportions. We argue that this is evidence that these cats do not have very recent domestic ancestry. However, from the morphological da ta it is highly likely that this gene pool also contains a contribution fro m earlier introgression of domestic cat genes.