Biologists reconstruct genome of 11,000-year-old “almost immortal” sexually-transmitted dog cancer

Canine transmissible venereal tumours (CTVT) is one of only two natural transmissible cancers, and could hold the key to better organ transplants in humans.

Veterinary biologists have discovered that a sexually-transmitted cancer found in dogs around the world first originated 11,000 years ago, making it potentially the oldest living mammalian creature.

The study from the Wellcome Trust’s Sanger Institute, published in Science, analysed the genome of canine transmissable venereal tumours (CTVT), a disease that is one of only two known cancers of its type to have been observed in the natural world (the other, transferred via bites, affecting Tasmanian devils). It’s not a cancer caused by the transfer of a virus, like with cervical cancer and the HPV virus in humans - it’s the transfer of actual cancerous dog cells from dog to dog.

“They are actually a parasite, they need to have their host in order to survive, but they’re actually derived from the same species as their host,” Dr Elizabeth Murchison, the study’s lead author, explained to me. “They’re quite a strange disease. They are an infectious disease, but they’re originally from the same species as their host, which makes them a kind of very tricky to combat.”

“It’s the oldest continually surviving mammalian lifeform that we know of,” she said. “It is almost immortal.”

Genome analysis of samples from a dog in Brazil and another Australia found that the cancer had undergone a huge number of mutations, in the order of two million, since it first began metastasising within the first dog to contract it.

Murchison said: “Between humans we each have about three million mutations, the natural variance that makes us different to other people. Similarly dogs have about three million natural variants that make one dog different to another dog. But cancers themselves, in humans, don’t tend to differ from their host very much. They usually have between 1,000 and 5,000 mutations in the genome that makes the cancer different to the host. Whereas this dog cancer has acquired about two million, which is almost making it like a different individual to the original host that gave rise to it.”

Relying on recent research which found that, within cancer patients, the number of mutations within a cancer correlates both to the type of cancer and the age of the patient, the study team were able to trace back in time to the point at which mutations must have started - giving the age of CTVT at 11,000 years.

Yet CTVT stayed within the small population where it first emerged for roughly 10,500 years, until suddenly spreading elsewhere around the globe - a time that coincides with the beginnings of the European age of exploration. While there’s no way to know where in the world the cancer first appear (yet), the earliest known historical mention of it is by a London doctor in 1810.

With the information from the origin dog’s genome, the team was able to create an image of what it probably looked like. Here's a video from the team further explaining their work:

What’s more, the cancer appears to have been caused by in-breeding.

“It was a relatively inbred individual,” explains Murchison. “Similarly, the Tasmanian devils are relatively inbred population - they live on an island, and they have a small population. The cancer might have originated in a dog that lived in an in-bred population, but from there it managed to adapt into all sorts of out-bred dogs. It can even survive in other species of canids, including jackals and coyotes and foxes. It’s pretty remarkable.”

Theoretically, this type of cancer could emerge at any time in any species, Murchison pointed out, but the experience of the dog and Tasmanian devil transmissible cancers - and from a third variant, which emerged briefly in a population of laboratory hamsters in the 1960s - seems to indicate that in-bred populations are more at risk. There are human populations which suffer from low genetic diversity around the world, and this research could be important in understanding transmissible cancers in the case of a variant appearing.

“These cancers have to overcome one of the most fundamental immunological barriers, and how they do it is still a mystery,” Murchison said. “It’s incredibly important to understand how they do it, as it has implications for how cancers evade the immune system, but also potentially how other infectious diseases might work, and have implications for how to design better methods for helping transplant recipient patients not to reject their graft transplant organs.”

Murchison is also keen to see if further research could help the endangered Tasmanian devil, whose variant is much more aggressive than CTVT and which can kill its host in a matter of months.

What the first dog to get CTVT may have looked like. (Image: Sanger Institute)

Ian Steadman is a staff science and technology writer at the New Statesman. He is on Twitter as @iansteadman.

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“Like a giant metal baby”: whether you like it or not, robots are already part of our world

For centuries, we have built replacements for ourselves. But are we ready to understand the implications?

There were no fireworks to dazzle the crowd lining the streets of Alexandria to celebrate Cleopatra’s triumphant return to the city in 47BC. Rather, there was a four-and-a-half-metre-tall robotic effigy of the queen, which squirted milk from mechanical bosoms on to the heads of onlookers. Cleopatra, so the figure was meant to symbolise, was a mother to her people.

It turns out that robots go back a long way. At the “Robots” exhibition now on at the Science Museum in London, a clockwork monk from 1560 walks across a table while raising a rosary and crucifix, its lips murmuring in devotion. It is just one of more than 100 exhibits, drawn from humankind’s half-millennium-long obsession with creating mechanical tools to serve us.

“We defined a robot as a machine which looks lifelike, or behaves in lifelike ways,” Ben Russell, the lead curator of the exhibition, told me. This definition extends beyond the mechanisms of the body to include those of the mind. This accounts for the inclusion of robots such as “Cog”, a mash-up of screws, motors and scrap metal that is, the accompanying blurb assures visitors, able to learn about the world by poking at colourful toys, “like a giant metal baby”.

The exhibits show that there has long existed in our species a deep desire to rebuild ourselves from scratch. That impulse to understand and replicate the systems of the body can be seen in some of the earliest surviving examples of robotics. In the 16th century, the Catholic Church commissioned some of the first anthropomorphic mechanical machines, suggesting that the human body had clockwork-like properties. Models of Jesus bled and automatons of Satan roared.

Robots have never been mere anatomical models, however. In the modern era, they are typically employed to work on the so-called 4D tasks: those that are dull, dumb, dirty, or dangerous. A few, such as Elektro, a robot built in Ohio in the late 1930s, which could smoke a cigarette and blow up balloons, were showmen. Elektro toured the US in 1950 and had a cameo in an adult movie, playing a mechanical fortune-teller picking lottery numbers and racehorses.

Nevertheless, the idea of work is fundamental to the term “robot”. Karel Čapek’s 1920s science-fiction play RUR, credited with introducing the word to the English language, depicts a cyborg labour force that rebels against its human masters. The Czech word robota means “forced labour”. It is derived from rab, which means “slave”.

This exhibition has proved timely. A few weeks before it opened in February, a European Parliament commission demanded that a set of regulations be drawn up to govern the use and creation of robots. In early January, Reid Hoffman and Pierre Omidyar, the founders of LinkedIn and eBay respectively, contributed $10m each to a fund intended to prevent the development of artificial intelligence applications that could harm society. Human activity is increasingly facilitated, monitored and analysed by AI and robotics.

Developments in AI and cybernetics are converging on the creation of robots that are free from direct human oversight and whose impact on human well-being has been, until now, the stuff of science fiction. Engineers have outpaced philosophers and lawmakers, who are still grappling with the implications as autonomous cars roll on to our roads.

“Is the world truly ready for a vehicle that can drive itself?” asked a recent television advert for a semi-autonomous Mercedes car (the film was pulled soon afterwards). For Mercedes, our answer to the question didn’t matter much. “Ready or not, the future is here,” the ad concluded.

There have been calls to halt or reverse advances in robot and AI development. Stephen Hawking has warned that advanced AI “could spell the end of the human race”. The entrepreneur Elon Musk agreed, stating that AI presents the greatest existential threat to mankind. The German philosopher Thomas Metzinger has argued that the prospect of increasing suffering in the world through this new technology is so morally awful that we should cease to build artificially intelligent robots immediately.

Others counter that it is impossible to talk sensibly about robots and AI. After all, we have never properly settled on the definitions. Is an inkjet printer a robot? Does Apple’s Siri have AI? Today’s tech miracle is tomorrow’s routine tool. It can be difficult to know whether to take up a hermit-like existence in a wifi-less cave, or to hire a Japanese robo-nurse to swaddle our ageing parents.

As well as the fear of what these machines might do to us if their circuits gain sentience, there is the pressing worry of, as Russell puts it, “what we’re going to do with all these people”. Autonomous vehicles, say, could wipe out the driving jobs that have historically been the preserve of workers displaced from elsewhere.

“How do we plan ahead and put in place the necessary political, economic and social infrastructure so that robots’ potentially negative effects on society are mitigated?” Russell asks. “It all needs to be thrashed out before it becomes too pressing.”

Such questions loom but, in looking to the past, this exhibition shows how robots have acted as society’s mirrors, reflecting how our hopes, dreams and fears have changed over the centuries. Beyond that, we can perceive our ever-present desires to ease labour’s burden, to understand what makes us human and, perhaps, to achieve a form of divinity by becoming our own creators. 

This article first appeared in the 23 March 2017 issue of the New Statesman, Trump's permanent revolution