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.

Azeem Ward
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Living the Meme: What happened to Azeem Ward and his flute?

In the first of a new series investigating what happens to people after they become memes, we speak to Azeem Ward, whose flute recital went viral in 2015.

The Sixties had Woodstock. The Nineties had Lollapalooza. The Tens – and, if we’re being honest, just a single year of them – had Azeem's Senior Flute Recital.

If you were inactive on the internet between 12 and 16 May 2015, you’ll be forgiven for not knowing who Azeem Ward is. After setting up a Facebook page for his end of year flute performance, the University of California student was inundated with over 100,000 RSVPs from the United Kindom, along with multiple requests to fly to England and play (for no apparent reason) Darude’s “Sandstorm” in Nando’s. After international news coverage, Ward – as all memes inevitably do – appeared on Jimmy Kimmel Live! to discuss his newfound fame. On 16 May, he had to turn hordes of people away from the 500 seat recital hall, and over 55,000 individuals tuned into a livestream of the event. Then, Ward disappeared. Not from social media, and not from the world, but from the internet’s collective consciousness.

Search interest in "Azeem Ward" over time

“I’d say no,” answers Ward, when I ask him whether, one and a half years later, he still receives any special attention or has any fan interactions. “I’m just regular Azeem now, and I’m okay with that. Regular me is a more focussed person that is not reacting to things that are happening around me.”

Ward is Skyping me from his home in Iowa, where he is getting his master’s degree in flute performance. He spends his time composing flute beatbox songs, learning how to produce music, and teaching a class on flute fundamentals at the university. “A lot of [the students] here in Iowa know what happened but they don’t go like: ‘Oh my God! It’s Azeem!’. It’s just like, ‘Hey, what’s up man? I saw that one thing about you on Jimmy Kimmel’.”  

The original Facebook event page

Ward regained his anonymity when he moved to Iowa, as many of his fellow undergraduate students in California recognised him because he was on the local news. “But the whole viral thing was a UK thing,” he explains, “It wasn’t really around the whole US.”

An Azeem meme

Four months after his famed flute recital, Ward did come to the UK and toured the country to perform as part of various university freshers’ weeks. “That was a crazy time,” he says, “I was over there for five weeks and played 22 shows in 12 different cities, all the way from London to Scotland.” His concerts were popular, though most people came to take a selfie or ask about how the recital happened, and only a few wanted to talk to him about music. Still, Ward profited from the events. “We did make some pretty good money," he says, admitting he earnt around $5,000. 

Despite clearly enjoying this time, Ward seems unfazed that his viral fame is now over. His only regrets, he says, are that he didn’t make any connections in the music business while in the UK, and that he didn’t have any social media accounts set up before he went viral, so there was nowhere for people to go to listen to his music. “When you go viral people hold onto that rather than taking you seriously as a musician,” he says. “Sometimes it annoyed me but sometimes I realised that I wouldn’t be there in the first place if it wasn’t for going viral.”

Azeem now, photo courtesy of Azeem Ward

So what advice would Ward give to the next person who finds themselves, unwittingly, the object of the internet’s affection?

“I'd say don't lose sight of what you've already been doing in your life, like keep your focus. I'd say that sometimes in your head you're like ‘Oh man, I have to do this now’, but you've just got to stay focussed on your goals. When you have your own path and you go viral you have a lot of people asking you to do all these different things. It was pretty intense – I’m not used to having a lot of people look at me and my actions, so I was pretty anxious at first. In the end I realised that I came to do what I came to do, and I had to go do it.”

Although Ward doesn’t miss being internet-famous, it is clear that going viral had an impact on him. He recalls the peak of the madness with telling clarity, sharing specific details such as "256 people” clicked attending in "four hours", and “then 512”, before 12,000 people RSVP’d overnight. Mostly, however, he seems very grounded, though he acknowledges it was “out of control” and “really crazy”.

Perhaps Ward feels this way because he received little in the way of negativity or hate. He fondly discusses memes that were created and art that was drawn about him, and the support of his family and friends. “Even though there were a lot of silly things going on, I managed to make it positive for the school,” he says. “I had no haters. Everyone was like ‘Damn, Azeem. Good job, man’.”

One day, Ward hopes to come back to London, although he is wary of returning. Not because of his viral fame, nor the number of selfies he might have to take with Nando's customers, but because of Brexit. Our conversation, like all post-June conversations, turns swiftly to the topic, and Ward asks me about the economy. “I was thinking about trying to do a doctorate over in London, but if things aren't going to be so good in a few years...” 

Ward admits he wouldn’t be bothered if he never went viral again. “When I think of something going viral, I think it has a point in time where there’s so much interest and then it goes away. I’d like to produce material and the attention to keep going up.” So do you want to be famous, I ask? “Do I really want to be famous?” he ponders. “Being famous is okay, I guess. But I want to be is respected and appreciated.”

To listen to Azeem’s music visit or Like his Facebook page.

To suggest an interviewee for Living the Meme, reach out to Amelia on Twitter.

Amelia Tait is a technology and digital culture writer at the New Statesman.