Adaptation to Starchy Foods Was Key to Dogs’ Domestication

Adaptation to a starchy diet may have been key to the domestication of dogs and cats

Join Our Community of Science Lovers!

Scientists have two theories for how dogs became man's best friend. One holds that people captured wolf pups and tamed them for their hunting and guarding abilities. The other, more popular explanation proposes that the advent of agriculture and the attendant development of human settlements in the Middle East around 10,000 years ago created scavenging opportunities for animals bold enough to exploit them and that wolves themselves thus initiated domestication. The new findings, published online January 23 in Nature, support this latter view and offer insights into how canine ancestors were able to take advantage of this novel resource. (Scientific American is part of Nature Publishing Group.)

Erik Axelsson of Uppsala University in Sweden and his colleagues analyzed DNA from 12 wolves and 60 dogs that represent 14 diverse breeds, looking for regions of the dog genome that evolved under selection pressure during domestication. Intriguingly, genes involved in the metabolism of starch showed up among the targets, along with genes that may have brought about behavioral changes such as reduced aggression and improved social-cognitive skills. In fact, the study revealed that during the domestication of dogs, selection acted on genes involved in all three stages of starch digestion, promoting mutations that facilitated the transition from a meat-centric diet to one heavy on starch.

Previous studies have shown that cats, too, may have domesticated themselves by dining on human leftovers. Although house cats have only a limited ability to metabolize carbohydrates, including starch, they possess a longer intestine than their wild counterparts, presumably to help digest the lower-quality sustenance they get from trash heaps compared with the all-meat diet they would be living on in the wild, according to geneticist Carlos Driscoll of the National Institutes of Health. In other words, begging for table scraps has been a long dog and cat tradition.

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

Adapted from Observations at blogs.ScientificAmerican.com/observations

COMMENT ATScientificAmerican.com/apr2013

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American