Fig. 1 Nature red in tooth and claw. Image: Wikimedia Commons.
My favorite kind of dog is not a specific breed, but a general body type: round with short legs. If you show me any dog I’ll squeal and try to pet it, but I make the highest of high-pitched noises when I see a pudgy, low-profile canine like a corgi, a dachshund, or a bulldog.
But maybe you prefer long, lean dogs like greyhounds or enormous fluffy Newfoundlands. Maybe you like mustachioed Scottish terriers or galumphing Great Danes or pint-sized Chihuahuas. The good news is, the World Canine Organization recognizes over 340 breeds of dog, so somewhere out there is a dog exactly the shape of the soft spot in your heart. But how did we end up with such a huge diversity of dogs in the first place?
Fig. 2 It doesn’t seem like these things should be the same species, but Chihuahuas (tiny, at bottom) and Great Danes (huge, bemused, at top) are both breeds of Canis lupus familiaris, the domestic dog. Image: Wikimedia Commons.
Studies indicate that domestic dogs split from their ancestors, gray wolves in central or southeastern Asia, about 14,000 years ago . Scientists can compare differences in the dog genome, or genetic code, with the wolf genome and use an estimated rate of change to back-calculate the time since the two lineages diverged.
Fig. 3 The majestic gray wolf (left) and the majestic Welsh corgi (right). A genetic innovation produced through artificial selection is responsible for the corgi’s shortened legs, or chondrodisplaysia. Images: Retron via Wikimedia Commons, Lily M via Wikimedia Commons.
Comparing the genomes of many breeds of dogs with wolves also gives us interesting information about what genes make our canine companions different from their wild relatives. One major area of difference lies in genes involved in neurological processes—for example, connectivity of nerve cells. These genes may be related to behaviors we associate with domestic dogs, such as reduced aggression . Genes involved in digestion also differ between dogs and wolves. Genes that regulate digestion of starches are expressed more in dogs, which is an indicator of their transition from the more carnivorous wolf diet to an omnivorous lifestyle as man’s most reliable table-scrap repository .
Traits that are associated with domesticated behavior in dogs have evolved in a slightly unusual way. While most species have evolved through natural selection, dogs are a special case of rapid evolution via artificial selection.
Artificial selection means that humans purposely breed animals with different combinations of traits in order to increase the likelihood of that trait in the offspring. To be clear, humans did not create wrinkly skin or floppy ears or any other domestic dog trait—rather, they preferentially bred dogs that already displayed traits they found desirable. Over thousands of years of breeding, these traits intensified and we ended up with artificially-selected canines who didn’t necessarily need to be good at hunting or running since they depended on us for food, shelter, and belly rubs .
Most of the diversity in dog breeds has originated in the last few hundred years alone. Dog breeders in the past weren’t working from a genetic basis—they were just carefully breeding dogs with physical traits and temperaments that made them well-suited to a variety of human purposes, from herding animals to guarding to companionship. However, because we can trace the rapid evolution of dog breeds through artificial selection, domestic dogs are an interesting avenue for research. Scientists have identified regions of the genome that may be responsible for the wrinkly face of the Shar-pei and the short legs of corgis and dachshunds , among other traits.
Although genetic science is advancing rapidly, we still don’t know which genes are responsible for ensuring that a dog will always prefer your bed and the exact spot where you are currently sleeping to the dog bed you bought them, no matter how sumptuous and full of orthopedic memory foam it may be.
In the meantime, tell your dogs from me that they’re good dogs and don’t forget that they are no longer adapted for hunting moose, so they deserve a treat right now. What good dogs!
Wang, G., Zhai, W., Yang, H., Fan, R., Cao, X. Zhong, L., Wang, L. Fei, L., Wu, H., Cheng, L., Poyarkov, A.D., Poyarkov, N.A., Tang, S., Zhao, W., Gao, Y., Lv, X., Irwin, D.M., Savolainen, P., Wu, C., and Y. Zhang. “The genomics of selection in dogs and the parallele evolution between dogs and humans.” Nature Communications 4 (2014): 1-9
Akey, J.M., Ruhe, A.L., Akey, D.T., Wong, A.K., Connelly, C.F., Madeoy, J., Nicholas, T.J., and M.W. Neff. “Tracking footprints of artificial selection in the dog genome.” Proceedings of the National Academy of Sciences 107 (2010): 1160-1165
More From Thats Life [Science]
- The Lovebug Effect
- CRISPR: Careful When Running with Genetic Scissors
- Bacteria: The Solution to Our Plastic Waste Problem?
- Maps are the ultimate scientific tool
- Why does it Taste like that? - How Saccharomyces Yeast Makes Beer
- Inherited Trauma
- WEIRD Science
- Hug an Oyster for Wildlife Conservation
- The Big Data Revolution
- If I Only Had A Brain (Organoid)
- Bang! 'Ouch' *Grab*
- Interview with Dr. Matthew Moore - Viral Perspectives
- Why are Parka Ruffs Made with Wolverine Fur?
- Why Don’t We Keep Resolutions?
- Genetic Diversity and Its Impact on Disease Treatment
- How Rat Fur can Help Diabetics Heal Wounds
- Using eDNA to Revolutionize Wildlife Conservation
- Fat is Good for Your Brain
- Why Wash Your Hands?
- A Unique Case of Arthropod Vision
- How does your clock tick?
- Expand Your Mind
- Going on Autopilot? Thank Your Place Cells
- Immunohistochemistry: One man’s illness is another man’s experimental verification method
- The Power of Fear: Four Ways Being Scared Affects Wildlife
- The crime-fighting field of forensic palynology
- Bioremediation - One Species’ Trash, Another’s Treasure?
- Brain Surgery… It’s Not Rocket Science!
- Changing the climate change conversation
- Why does alcohol make you dizzy?
- It’s Not Science Fiction, Chimeras Are Real
- A Peanut A Day Keeps the Allergist Away
- The Rise of Sourdough and Mason Jar Ecosystems
- Radioactive Bananas, Teenage Mutant Ninja Turtles, and Greenhouse Gases, OH MY!
- Uncharted Intellectual Territory: Science Isn’t Linear
- It’s a Trap! How Looks Can Be Deceiving in Habitat Selection
- The Feelings that Linger: Good vs. Bad
- Go With Your Gut...
- Live Fast, Die Young: Why Some Animals Die After Mating
- New Culture, New Microbiome, New Problems
- If Only There Were a U.S. Census Question About Biodiversity…
- How An Invasive Plant Helped Fuel The Largest Wildfire You’ve Never Heard Of
- Human Eye Structure Makes No Sense…Or Does It?
- The Price of Pigment on Your Immune System
- Midnight Snacks Could Be the Death of You
- Lobster Fight Club
- Making a Murderer - A Matter of Biology?
- Got Lactase? Breaking Down the Enzyme
- Why Do I Shiver When It’s Cold?
- Crap you didn’t really need to know
- You Can't Observe A Lot Just By Watching
- What Do You Do When It's Too Hot to Move?
- 5 Fun Facts about Hormones
- Death stinks - literally
- Why the sea salt fad could be very bad
- Henry's Pockets: A Poem
- Biology Superpowers: X-Ray Vision
- How to Expand Your Senses by Reading a Blog Post
- What's up with bat echolocation?
- Seeing is Believing - How Can We Visualize Tiny Colorless Bacteria?
- Saving water is no longer a matter of how short our showers are · Water balance in a man-made world
- Double Digestion in Rabbits · Why Does Mopsy Eat Her Own Poop?
- Should I say sex or gender? Pt. 2
- Should I say sex or gender? Pt. 1
- How To Catch Hard-to-Catch Fish?
- Finding the Perfect Partner
- Is your gut trying to kill your resolve? · Mind over microbe
- Why Do Mothers Mother?
- GMO! The Places You'll Go!
- New-Fangled Paleontology · Really Old Fossils, Really Strong Predators, and Cool New Tech
- A Brief History of Evolutionary Thought, part III
- Saving face: transplanting our most distinctive features
- A Brief History of Evolutionary Thought, part II
- DNA as a solution for data storage · DNA - Nature’s Hard Drive
- A Crash Course in the Coolness of Mitochondria · Mitochondria: The Underrated Organelles
- A Pollinator’s Job Description and Why We Should All Care About Them · Pollination 101
- You May Say I’m Biased, But I’m Not the Only One
- The evolution of one of the greatest medical discoveries in history. · The Path of Least Resistance: Our Relationship with Antibiotics
- Mother Nature’s History Book · Estimating the Age of Life Long-Gone
- Proprioception as a vital sense · Know Your Limb-its
- Man’s Best Artificially-Selected Friend · Your Dog is a GMO Wolf
- Better Safe Than Sorry: The Pesticide Industry is Getting a Revamp
- Sometimes scientists have to get creative in order to effectively do science – especially on a budget. · The Bizarre Shopping List of a Determined Scientist
- Insects Get Sick Too: The Study of Insect Pathology
- Our teeny tiny friends and their huge potential · Employee of the Month - Hire a Microbe to Do Your Work
- A Brief History of Evolutionary Thought - Part I
- The Effects of Custom Build Paradise · Artificial Islands
- To B(PA) Or To Not B(PA): Regulating Endocrine Disruptors
- Bioluminescence truly looks like it is nothing short of sorcery, and although this naturally occurring phenomenon is well studied and explained, that does not take away from its beauty. · Fireflies of the Ocean: Lighting up the Dark with Science
- Part II - Cases of altruism in the animal kingdom · Charity cases in nature - when are animals more likely to be altruistic?
- Part I - Why true altruism is a rare behavior in the animal kingdom · Being selfish means staying alive
- Penguins and other strange things we study from space
- Pseudoreplication and the Art of Biological Statistics
- What is wrong with my tomatoes?...And other plant disease questions · Why did orange prices increase?
- How fecal microbiota transplants can improve lives and possibly save them · The Wonders of Fecal Transplants
- The scientific facts behind the safety and efficacy of childhood vaccines · Calling the Shots - Discussing Vaccines
- 3D Printing for Fun and Science
- What is wrong with my tomatoes?...And other plant disease questions · What is Phytopathology?
- Medical Mysteries Still Surrounding Zika Virus
- More ›