By Tracie Korol
Dogs straddle two worlds. They are the cute and snuggly co-habitors of our lives. But somewhere underneath, every now and then, if you squint, you can see in your Best Friends the hint of a wild, lean and rangy wolf. So, how exactly did that happen?
Scientists studying DNA from wolves and dogs think there’s a reason that dogs evolved into adorable, soft, sometimes squishy pets while wolves remain lean and sinewy, with a sort of rough appeal. The reason has to do with their ability to digest carbs.
Scientists at Upssala University in Sweden recently completed a study (“The Genomic Signature of Dog Domestication Reveals Adaptation to a Starch-rich Diet”) printed in the journal Nature, that compared the DNA of 12 wolves and 60 dogs including cocker spaniels, schnauzers, golden retrievers and 11 other breeds. They found there were key differences that allowed dogs to digest carbohydrates far more easily. The presence of changes to starch and sugar-processing genes would have allowed early dogs to make the most of the scraps they could scavenge from human settlements, helping them to thrive despite abandoning the wolf pack lifestyle.
They looked at gene variations the dogs had in common with each other, but not with the wolves. What they discovered is that dogs have many more genes that are involved in, and in some cases absolutely essential to, starch or fat metabolism. One of these genes, AMY2B, is responsible for making an enzyme called alpha amylase, which is extremely effective in digesting starch Dogs have five times as much alpha amylase activity as wolves.
What’s really interesting about this study is not necessarily the study itself but rather the questions it has raised. The study itself suggests that the domestication of dogs was a form of selection as the canines that were already able to easily digest carbohydrates were able to survive easier apart from the pack and consequently became domesticated. While other scientists have suggested that these genes may have become adapted after the domestication of dogs as the carb heavy diet promoted the specialization of the carbohydrate digestion genes. So, rather like the question of which came first the chicken or the egg, science now has a different question to ponder, which came first domestication or the genes?”
Researchers envision the evolution of wolves into dogs happening something like this: there were some wolves hanging around human settlements. They were eating meat leftovers. They kept hanging around the humans. The humans started to eat roots, fruits and porridge. The wolves that could digest carbs started to eat scraps from this expanded, more carb-heavy diet, and hung around more and more, and ate more carbs, while the wolves that could not stayed farther away from the human settlements, as their cast-off garbage was not as appealing. And, a couple billion loaves of bread later, we got dogs.
However, do not think that with this info in hand you can go back to feeding your pal a bowl full of the cheap kibble. You know, that ground corn and wheat starch stuff doused in mysterious “animal” fats. Just because they can digest these components doesn’t mean they should. Just as a diet heavy in white flour, sugar, French fries and buttered grits can make you chubby and diabetic, so is the same for your dog. Wolves may be largely carnivores, but domestic dogs tend to be omnivores. Meats, fish, vegetables, fruits and whole grains will make for a happier, healthier, almost-a-wolf Best Friend.
