A real-life Feejee Mermaid

September 18th, 2008

One from the dark side of science – a cancerous tumour that breaks free of its host to find a new home.

The best thing about science and the universe is that it routinely trumps fiction on the pure awesomeness scale.  It seems there is nothing in the minds of men that can’t be bettered by the natural world around us.  Take for instance, the Feejee Mermaid.  Cast your mind back to the late Nineties and you may remember a twee little science fiction show called the X-files.  One episode (S02E01, to be exact) saw the intrepid agents chasing after a parasitic twin (the ‘Feejee Mermaid’ in question) that bored out of its brother and sought out a new home in several unwilling hosts.

In the real world, Dr Robin Weiss has released a study showing that something similar is happening in dogs.  Canine Transmissable Venereal Tumour, as the name suggests, is a cancer spread by hot doggie-loving in alleys and parks around the world.  It’s the first case of a transmissible cancer.  I know some of you are thinking ‘what about cervical cancer?’ and it’s true that this is a cancer and it’s spread by sex.  However, it’s not the cancer that is spread by sex but a virus (Human Papillomavirus), which in turn causes cervical cancer (or warts if you’re lucky).  Canine Transmissible Venereal Tumour is different as it’s the actual tumour itself that spreads from dog to dog.  Weiss estimates that somewhere around 250-1,000 years ago, a wolf or close relative developed this tumour.  Somehow, through Nature’s endless wonder, this tumour managed not only to spread during sex, but also to survive in its new host.  That’s the same tumour, with the original DNA makeup, now present in dogs all over the world.  OK, so the tumour isn’t bursting out of their stomachs and hunting down new hosts but as far as biology goes it’s not far off. Here’s a clump of cells carved out of one dog that has liberated itself and now survives and spreads through dogs all round the world, and is still living long after its original parent died.

What I want to know is whether the tumour can be recognised as an definite organism.  Sure, it’s incapable of living on its own, but then the same goes for all viruses.  So is this the birth of a new species?

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