13 Jul 2017

Canine DNA and 'Darwin's Dogs'

From Our Changing World, 9:07 pm on 13 July 2017

Dogs have come a long way from their grey wolf ancestors.

About 33,000 years ago, somewhere in Asia (the exact location is a matter of scientific disagreement) we began the process of domestication – or did the dogs domesticate us? Either way, they won their way into our hearts and homes.

Big and small. Brown, black and white - assorted dogs

Darwin's Dogs is interested in the personalities of various dogs, and whether this is controlled by different genes. Photo: RNZ / Alison Ballance

Today there are nearly 340 recognised dog breeds, many of them created within the past two hundred years. There are also innumerable mongrels and ‘bitzers’, made from a bit of this and a bit of that.

From chihuahua to Irish wolf hound, long-haired and short coated, spotted and plain, our pampered pooches boast a wide array of physical characteristics.

And as any proud dog owner will tell you, they also vary hugely in temperament.

It’s this variation in personality that interests Elinor Karlsson from University of Massachusetts Medical School and the Broad Institute at MIT in Harvard.

More pooches

Some of the 30-or-so dogs that donated their saliva (and their DNA) to science and the Darwin's Dogs project. Photo: RNZ / Alison Ballance

Elinor runs a citizen science genetics project called Darwin’s Dogs, and she is interested in the relationship between genetics and behaviour.

“It’s a collaboration between scientists and dog owners,” she says, “to see if we can study our pet dogs and understand behaviour in pet dogs as a way to get a window in how our brains work – not just dog brains, but also human brains.”

Collecting a sample of dog saliva

Gathering canine DNA involves collecting dog saliva on a cotton swab. Only one swab got accidentally swallowed in Dunedin! Photo: RNZ / Alison Ballance

So, why dogs?

“Dogs are particularly interesting because every single dog lives with people who spend a huge amount of time watching them,” says Elinor. “And so the idea of this project is that rather than try and figure out what a dog’s behaviour is as scientists, we’ll just ask the dog owners. And they can tell us, because people really know their dogs. Also, people really like talking about their dogs.”

Darwin’s Dogs is mostly an online project. People sign up and fill out a detailed questionnaire about their dog. Then they collect a saliva sample from their dog and send that in for DNA testing.

Because of regulations around sending genetic samples through the mail, most of the dogs involved are in the United States. But on a recent trip to New Zealand, Elinor was excited to collect canine DNA samples from about 30 Dunedin dogs.

People and dogs

Elinor Karlsson (left) briefs Dunedin dog owners on how to collect DNA samples. Photo: RNZ / Alison Ballance

Is she expecting New Zealand dogs to be any different from American dogs?

 “I think there’s going to be some interesting differences, actually. There’s a really strong working dog history to the dog population in New Zealand, and then there were also the dogs that Maori brought here. And both of those things could be having a really strong influence on the genetics of the New Zealand dog population.”

Three different dog breeds.

There are about 340 recognised dog breeds in the world. Photo: RNZ / Alison Ballance

Elinor says the first dog genome was sequenced back in 2005, and cost a lot of money to achieve. The current study is possible because the cost of sequencing an entire genome now costs just a few hundred dollars, so it is a relatively simple process to collect the genomes of many dogs.

“All we do is we take hundreds or thousands of dogs that are incredibly anxious and hundreds or thousands of dogs that are totally relaxed, and we compare them. And we look for places on the genome where those dogs tend to be different from one another. And once we’ve found those places then we go in, and look to see what genes might be there and what they’re doing.”

Elinor hopes that identifying the genes that control personality traits such as anxiety or obsessive compulsive disorder in dogs will have direct implications for understanding the same conditions in humans.

“What’s really driving this research is that if we can figure out what pathways in the brain are actually involved in something like obsessive compulsive disorder, then we might be able to design a drug that particularly targets that pathway. But in order to do that we need to find the pathways to begin with.

“People can tell us part of the story, but by adding the dogs in they might be telling us a different part of the story.”

Black and white dog called Sprockett.

Modern dogs are descended from grey wolves, and the process of domestication began about 33,000 years ago in Asia. Photo: RNZ / Alison Ballance