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When you think about dog food, you probably picture more meat than potato. But a new study finds that, unlike wolves, dogs have genes that allow them to digest starch. That evolutionary adaptation may have helped fuel their domestication. The report is in the journal Nature. [Eric Axelsson et al., The genomic signature of dog domestication reveals adaptation to a starch-rich diet]
Dogs and wolves hail from a common canine ancestor. And though you can still see a strong resemblance, many traits distinguish the two today. Wolves have larger teeth and skulls than dogs do. And they’re far less likely to bring you your newspaper and slippers.
To figure out how such differences might have evolved, researchers compared the DNA of a dozen wolves and 14 different dog breeds, from cocker spaniels to German Shepherds. And they found 36 places where the dogs’ genes stray from those of the wolf. Some of these genes have to do with the brain, but a surprising number help pooches process carbs. [See also Kate Wong, Adaptation to Starchy Diet Was Key to Dog Domestication]
That metabolic trick may have made it easier for dogs to stomach hanging around with humans, particularly once people started farming. The leftover grains in the scrap heap may have attracted animals that, over time, evolved an ability to carbo-load. And ultimately convinced them to stay.
—Karen Hopkin
[The above text is a transcript of this podcast.]
[Scientific American is part of Nature Publishing Group.]
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3 Comments
Add CommentThis fits with the hypothesis that dogs evolved from an intermediary form rather than directly from wolves. It has been suggested that wolves that lived on the outskirts of human settlements or followed tribes developed a somewhat mutualist relationship with humans long before humans domesticated them. These proto-dogs lost their fear of humans and became habituated to human food as they scavenged what we left behind. Perhaps we benefited from having them around, scaring off other predators on perhaps reducing vermin either directly by preying on them or indirectly by consuming human waste and garbage that vermin would eat. The similarities of human communities to wolf and proto-dog communities eventually led to a very strong mutualist relationship between the two species as we began to raise them within our communities. It is really quite incredible when you look at these creatures and realize that they have evolved to be our best friends.
Reply | Report Abuse | Link to thisI suppose the report is short necessarily, but I think it should mention that grains and other vegetables make up a substantial portion of typical commercial dogfood, with meat either being absent or substantially a smaller portion of such food. Historically, dogs sometimes have been fed only a vegetable diet at least part of a given year. If dogs couldn't digest starches, they could not survive on such forms of dogfood.
Reply | Report Abuse | Link to thisPerhaps dogs evolved with H. sapiens, both adapting to the same diet. As ours changed to a more starch-based diet with the advent of farming, only those that could adapt stayed with us.
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