by our Science-Health correspondent
Wildcat populations have been devastated by disease, loss of habitat and inter-breeding with domestic cats. Dr Bill Ritchie would like to do something about it: repopulate the glens with pure native Scottish wildcats.
One of the original ‘Dolly’ team scientists, embryologist Dr Ritchie has commenced work aimed at cloning rare Scottish wildcats in danger of disappearing. There are an estimated 400 left in the wild and the number is dwindling.
Dr Ritchie was part of the team of embryologists at the Roslin Institute in Edinburgh who in February 1997 announced they had created Dolly, ‘the sheep that shook the world’. Dolly the sheep was the first cloned mammal ever to be made from an adult differentiated (somatic) cell using the technique of somatic cell nuclear transfer.
Somatic cell nuclear transfer involves taking differentiated adult cells from a mammal, multiplying the cells in tissue culture then crucially starving the cells of nutrients. This drives the cells into a dormant, or quiescent state, and produces many identical copies of the same cell with identical quiescent nuclei.
The cell nucleus from a quiescent adult cell is subsequently transferred into an unfertilised oocyte (developing egg cell) that has had its nucleus removed. The hybrid cell is then stimulated to start cell division again by electric shock, and when it develops into a blastocyst it is implanted in a surrogate mother.
Dr Ritchie believes this technique should work for the Scottish wildcat because previously “several cat species have been cloned using the domestic cat, as well as the wolf using dog eggs”. Scottish wildcats ‘hybridise’ with domestic cats and this is gradually and inevitably wiping out the native wildcat. There is hopefully a positive, added Dr Ritchie: “We can probably use the oocytes (the eggs) from the domestic cat to actually act as the recipients for the nucleus from the wildcat.”
For the Scottish wildcat, time is of the essence since there are only 150 breeding pairs left in the wild.
Dr Ritchie added: “One of the estimates that I’ve read recently suggests that the wildcat will be completely gone in about five years. So, if we don’t start doing things now, if we don’t start getting cells from animals which are pure bred then I don’t know what’s going to happen in the future. We’re just going to lose that animal.”
In practical terms the cloning process should be feasible. It’s estimated there are over 400 pure-bred wildcats surviving in parts of the Highlands, so catching an adult is step one – they are incredibly timid and savagely wild. Once captured, there are further necessary steps to take to produce pure bred wildcats.
Dr Ritchie: “It is very difficult to find pure wildcats due to their crossing with domestic animals, but modern scientific techniques are able to select animals which are pure bred. Cells collected from these animals, by taking a small piece of skin, would be cultured to supply cells for the cloning process”.
Next, you add an egg. In the Cairngorms, there is currently a cat spaying project to prevent inter-breeding with wildcats which could provide a useful source of viable eggs (oocytes) for the cloning process. A reasonable surrogate mother for blastocyst implantation would be a house cat-wildcat hybrid which should theoretically bring to term ‘pure wildcat kittens’.
In August last year, bosses at the Royal Zoological Society of Scotland RZSS’s Highland Wildlife Park said a project to clone wildcats was being discussed – but is still in its early stages.
The immediate obstacle to cloning the Scottish wildcat is financial. The cost is reckoned to be in the region of hundreds of thousands of pounds Sterling before work can fully get underway. Several organisations are already helping contribute to the project but much money is still required.
Money can’t buy you love, but it might just elicit a purr or two.