Home
Science & History
Print|Email|Text Size: ||
Scientists Searching for Clues to The First Dog

JB: What’s going on in your lab now?

AB: We’re collecting DNA samples and the genetic information we need so we can start piecing together what’s going on in these interesting but largely neglected free-ranging dog populations. We are seeking insights into dog population history to discover patterns of selection around certain genes that can then become the basis of further study. Our work is very hypothesis-driven. We have certain hypotheses about how dogs evolved, and we try to collect the right samples to test these hypotheses.

As geneticists learn more about how genetic variation controls complex traits in purebred dogs, we find it’s quite different than what we see in humans. Why? There are at least two competing hypotheses, and by gathering data from free-ranging dogs, we can start testing them to figure it out. Some of this gets into technical discussion about genetic architecture, recombination, epistasis and pleiotropy and such, so I’ve avoided getting too academic. But I also don’t want to be dismissive of it since those technical, hypothesis-driven aspects of the project are the bread and butter of my lab in terms of student training.

JB: In longitudinal studies such as the Morris Animal Foundation’s Golden Retriever Lifetime Study, researchers gather information from participants’ DNA and then match what they find to traits the test dogs may display over a lifetime. Will you have an opportunity to see how, for example, an immunesystem mutation affects a village dog’s health as it ages?

AB: Our project is a huge undertaking, and there’s a ton of data we’d love to gather on each dog but just simply aren’t able to since, at this point, we’re focused on sampling as many dogs from as many populations as possible to maximize the amount of diversity we can analyze. I really don’t want to overstate what we’re able to do in one visit to check out a dog and draw blood, which is limited to looking for genetic signatures in the genome of these dogs showing signs of selection and/or local adaptation.

But, since we have a fairly good idea of what genes do in modern dogs, at least in a rough sense, if we see a genetic signature in village dogs for positive selection around a gene we know is involved in immune function (for example), that’s a big discovery.

JB: At the risk of oversimplifying, say you’re looking at a region that you know to be linked to a negative trait and you see that the switch is turned off in the village dog DNA and turned on in modern dog DNA—would you feel that you’d found a “smoking gun”?

AB: It’s possible. Then, of course, as you allude, we would want to go back, look at dogs carrying that mutation versus other dogs, and see if there are different health outcomes. Perhaps [dogs with the mutation] are more resistant to intestinal parasites or perhaps they are more prone to autoimmune disease or something. Until we find the mutations, it’s a bit speculative to make predications about what exactly the findings will mean to owners. This is certainly “basic research” in the purest sense.

JB: In people, size is determined by hundreds of genes, each with a small effect. In purebred dogs, body size can be regulated by a single gene. Is this unique to dogs?

AB: It depends. There are other traits in other species controlled by a couple of loci [location of a gene on a chromosome]. I would argue that yes, it’s pretty unique. Whether or not dogs are special in that there is something about their genome that predisposes them to this type of diversity, or perhaps because humans worked so hard at creating them, we don’t know. This debate is still raging in the literature. It is definitely the case that genes have many, many effects. Rather than being a blueprint in which each gene is responsible for just one part of building the whole organism, the genome is more complicated, with each gene taking on different roles at different times or in different tissues.

JB: Do multiple-trait relationships also show up in village dogs?

Print|Email
CommentsPost a Comment
Please note comments are moderated. After being approved your comment will appear below.
Submitted by Anonymous | May 24 2013 |

Regarding the title of the topic "Scientists Searching for Clues to The First Dog", the Archaeological Institute of America has a few articles worthy of review:

May 22, 2013 - Prehistoric Dogs Were More Than Hunting Companions

EDMONTON, CANADA—Robert Losey of the University of Alberta studied prehistoric burials of dogs [http://news.discovery.com/animals/pets/prehistoric-dog-lovers-profiled-1... around the world. He found that dog burials were more common in regions where the human population was dense, the dead were buried in cemeteries, and people ate a lot of aquatic foods, even though it had been thought the dogs were kept by humans primarily for hunting terrestrial game. In Eastern Siberia, where dog domestication is estimated to have occurred 33,000 ago, dogs were only buried for the past 10,000 years, and then only when a human was also being buried. “I think the hunter-gatherers here saw some of the dogs as being nearly the same as themselves, even at a spiritual level. At this time, dogs were the only animals living closely with humans,” Losey said. For example, one dog had been buried wearing a necklace made of four red deer tooth pendants, a human fashion at the time.
http://www.archaeology.org/news/896-130522-domestication-dogs-burials

May 20, 2013 - Are Dogs and Humans Evolutionary Partners?

BEIJING, CHINA—Geneticist Guo-dong Wang of the Chinese Academy of Sciences and his team analyzed the DNA of four gray wolves, three indigenous Chinese dogs, a German shepherd, a Belgian Malinois, and a Tibetan mastiff. Their results indicate that gray wolves split from Chinese dogs some 32,000 years ago. They then compared corresponding genes in dogs and humans, and found that domestic dogs and their human partners experienced similar changes in digestion, metabolism, and brain chemistry as they evolved together. “As domestication is often associated with large increases in population density and crowded living conditions, these ‘unfavorable’ environments might be the selective pressure that drove the rewiring of both species,” the team wrote.
http://www.archaeology.org/news/885-130520-dogs-humans-domestication-gen...

Thanks for the opportunity to show my enthusiasm as a animal lover. Please don't forget that we are from the animal kingdom too.:) Loving an animal is what makes life beautiful!

More From The Bark

By
Michael W. Fox
By
The Bark
By
Amy Young
More in Science & History:
Freud Sang to His Dog
Myths: Loyalty Rewarded
Body Language
Is Your Dog Waiting For You?
The Wolf in Your Dog
Alexandra Horowitz, The Canine Mindseeker
DNA Testing
Buffon
Can DNA Decipher the Mix?