Genetic swamping of the critically endangered Scottish wildcat was recent and accelerated by disease -a brief response

 

The European wildcat population in Scotland is considered critically endangered as a result of hybridization with introduced domestic cats, though the time frame over which this gene flow has taken place is unknown.

Quadrupeds by Bewick as well as many other sources (see The Red Paper 2022 Vol. II: Felids) it is quite clearly stated that the British wild cat has only survived up to the 18th/19th centuries due to interbreeding with domestic cats. It was believed at that time that interbreeding had started taking place probably after the Roman conquest of Britain (this is dealt with in more detail in The Red Paper Felids).

The biggest problem here is that the term “European wild cat” is used. The DNA does indeed match the European wild cat for a very simple reason; they were imported into the UK for many private as well as travelling menageries as well as for sport -we have at least three pairs “turned down” (released) in North of England shooting territories in the 1920s. Wild cats escaped and there is enough anecdotal evidence as well as taxidermy to prove that wild cvats were in England and hybridising in the 1920s, 1930s and 1940s.

Some of the most noted zoologists/naturalists and ‘sportsmen’ (hunters/shooters) on visiting museum collections in the late 1800s and early 1900s reported how they saw no true wild cat specimens but only hybrids and they used well established wild cat diagnostic features to show this. I have not found one UK museum with any taxidermy of what we define as true wild cats and all were acquired -/+1900. A meeting of Scottish naturalists and zoologists in 1897 declared that what would have been called the true Scottish wild cat had become extinct by the 1860s (Red Paper Felids). The only collection of genuine Scottish wild cats I know of is the Extinct Fox and Wild Cats Museum and these are specimens from the 1830s when the species was becoming rare.

Via contemporary records, and many exist and are not hard to find, we can date wild cat-feral domestic hybridisation having been known and recorded as far back as the Medieval period but more ‘modern’ accounts exist from the 18^th century and that is a date well beyond the claimed

“ onset of hybridization was only within the last 70 years” (ie. 1953)

Here, using genome data from modern, museum, and ancient samples, we reconstructed the trajectory and dated the decline of the local wildcat population from viable to severely hybridized. We demonstrate that although domestic cats have been present in Britain for over 2,000 years, the onset of hybridization was only within the last 70 years.

The question is where did the “ancient samples” come from -Europe? If so then they cannot be relevant to the Scottish wild cat. Britain was isolated from continental Europe over 10,000 years ago when Doggerland was submerged. Foxes, wolves and wild cats remained isolated and not affected by island dwarfism. We know that foxes had developed three types to survive in their specific habitats -the Greyhound or mountain fox (the largest), the Hill or mastiff fox (smaller than the former but of sturdy build) and the Common or cur fox -small and living near to human settlements. The counterpart to the Old fox existed in Western Europe until hunting allowed the red fox to move in.

We need far more research on the Western European wild cats but it is possible that they were similar to those in Britain the size and power of which were legendary and even packs of dogs sent to hunt a wild cat were given leather studded collars to prevent them being killed. Wild cats were noted for their size and when still to be seen in England were known as “The English Tiger” as term later used for the Scottish wild cat -”The Highland Tiger” which indicated that the centuries of ‘sporting’ eradication as well as wiping out local populations for the bounties paid had pushed the true Scottish cat further north. What is seen today is the same as what we see in the red fox -imported animals that were released or escaped and due to various factors (Red Paper Felids) became known as the Scottish wild cat.

Our analyses reveal that the domestic ancestry present in modern wildcats is markedly over-represented in many parts of the genome, including the major histocompatibility complex (MHC). We hypothesize that introgression provides wildcats with protection against diseases harbored and introduced by domestic cats, and that this selection contributes to maladaptive genetic swamping through linkage drag. Using the case of the Scottish wildcat, we demonstrate the importance of local ancestry estimates to both understand the impacts of hybridization in wild populations and support conservation efforts to mitigate the consequences of anthropogenic and environmental change.

There is no true existing Scottish wild cat and has not been one since the 1860s and what is now called the Scottish wild cat has been surviving by breeding with feral domestic cats and both are snared, shot and killed in other ways on private estates despite legal ‘protection’[ for the former and just a survey I carried out two years ago on Scottish wild life groups showed how ‘diagnostic features’ were argued about “A short tail and it’s a wild cat” and “No, a short tail is proof of a hybrid” and for that reason gamekeepers and others can kill the cats with impunity because “no one can prove a cat is a genuine wild cat”. The feral domestic cat has been keeping what we now know as Scottish wild cats going as a population for a long time and the idea of a “pure blood” is something of a fantasy. Any cats released now as Scotti8sh wild cats will still be under threat while they and feral domestics can be killed with impunity.

Here, we generated and analyzed whole-genome sequence data to date the onset of significant hybridization in Britain and assess potential consequences for wildcats carrying introgressed

domestic cat DNA.Our data comprised domestic cats, 30 wild living individuals from Scotland sampled across the hybrid swarm, and six wildcats from the UK captive population (founded on wild animals from Scotland). Seven additional wildcat samples were obtained from Germany and Portugal. We also made use of low-coverage, whole-genome sequence data

from historicandarchaeological samples, specifically fourputative Scottish wildcats (museum specimens sampled 1906–1939, 0.3– 4.73) and two archaeological samples from Medieval (16th century, 0.93) and Mesolithic Britain (8,459–8,272 cal. BP, 0.23).3 Additional low-coverage genomic data (0.02–0.073) were obtained from 20 museum samples of putative Scottish wildcats.

Really the Mesolithic specimens would not show a great deal when compared to the current Scottish wild cat. DNA wo9uld probably work better on the oldest and specimens prior to the 1860s.

This study is interesting but has major flaws in that it appears that no historical documents, papers or books were consulted that might have given a better informed appraisal of the study material. If there is no knowledge of the historical records, of the mass importation of wild cats (and other species found in the UK due to the original animals being killed off by hunting -the red squirrel rather like the Old foxes and wild cats were amongst the species hunting killed off by the 1860s and hares, foxes, wild cats, deer and others were imported so any modern DNA testing will show a match to European species).

Without the basic knowledge that wild cats in the UK survived up until the 1860s because of hybridisation and without Old wild cat specimens the study means nothing. Wild cats from Germany and Portugal are not from the Old isolated British population of wild cats but on a continent where a species can spread out they would mat6cvh up with the European wild cat we see today -again there is no reference to wild cats being trapped and transported to other countries for repopulating or sport and that is very significant information that is needed prior to carrying out a study such as this.

An interesting read but not the claimed breakthrough study as reported online and in the media. We still know nothing of the true British (Scottish, Welsh and English) wild cats