Two studies published today in Current Biology and involving new archaeological and genetic evidence rewrites the history of cats in Europe.
The international team of researchers sequenced and analysed both wildcats and domestic cats including 48 modern individuals and 258 ancient samples excavated from 85 archaeological sites over the last 8,500 years. They then assessed the patterns of hybridisation (or interbreeding) after domestic cats were introduced to Europe over 2,000 years ago, and came into contact with native European wildcats.
The results of the studies demonstrate that, since their introduction, domestic cats and European wildcats generally avoided mating with each other. About 50 years ago in Scotland, however, that all changed and rates of interbreeding between wildcats and domestic cats rose rapidly. This may have happened as a result of dwindling wildcat populations and a lack of opportunity to mate with other wildcats.
Jo Howard-McCombe from the University of Bristol's School of Biological Sciences and the Royal Zoological Society of Scotland explained: “Wildcats and domestic cats have only hybridised very recently. It is clear that hybridisation is a result of modern threats common to many of our native species.
"Habitat loss and persecution have pushed wildcats to the brink of extinction in Britain.
"It is fascinating that we can use genetic data to look back at their population history, and use what we have learnt to protect Scottish Wildcats.”
Professor Greger Larson, from the University of Oxford, said: “We tend to think of cats and dogs as very different. Our data suggests that, at least with respect to avoiding interbreeding with their wild counterparts, dogs and cats are much more similar to each other than they are to all other domestic animals. Understanding why this is true will be fun to explore.”
Professor Mark Beaumont, from Bristol’s School of Biological Sciences, said: “The nature of the Scottish wildcat and its relation to feral domestic cats has long been a mystery. Modern molecular methods and mathematical modelling have helped to provide an understanding of what the Scottish wildcat truly is, and the threats that have led to its decline.”
Domestic animals including cattle, sheep, goats, dogs, and pigs have been closely associated with people since the emergence of farming communities 10,000 years ago. These tight relationships led to the human-mediated dispersal of plants and animals well beyond their native ranges.
Over the last decade, genomic sequences of modern and ancient individuals have revealed that, as domestic animals moved into new regions, they interbred with closely related wild species, which has dramatically altered their genomes. This pattern has been seen in every domestic animal, except dogs. And now we know this is also true of cats.
The two studies, published in the journal Current Biology, were carried out at universities in Munich, Bristol, Oxford and the Royal Zoological Society of Scotland.
Paper
'Genetic swamping of the critically endangered Scottish wildcat was recent and accelerated by disease' by Jo Howard-McCombe et al. in Current Biology [open access]