Science

Did dogs evolve in dumps?

Research scientists believe that dogs’ penchant for bin-rummaging could be intrinsically linked with their evolution from the wolf.

A new study of dog genetics has revealed that numerous genes involved in starch metabolism backs up an idea that some dogs emerged from wolves as a result of digesting scavenged food from early farmers.

Archaeological evidence suggests dogs’ domestication occurred thousands of years ago. One suggestion as to how this happened is dogs emerging from ancient hunter-gatherers’ use of wolves as hunting companions or guards.

Another opinion states that domestication started with wolves stealing food leftovers eventually living permanently around humans as a result.

Speaking to the BBC, Dr Erik Axelsson from Uppsala University expands upon this notion: “This second hypothesis says that when we settled down, and in conjunction with the development of agriculture, we produced waste dumps around our settlements; and suddenly there was this new food resource, a new niche, for wolves to make use of, and the wolf that was best able to make use of it became the ancestor of the dog.”

Dr Axelsson and colleagues examined the DNA of more than 50 modern dogs of differing breeds and compared their genetic information with those of 12 wolves. The team scanned DNA sequences of the two types of canid and identified 36 regions containing genes important in the rise of the domesticated dog. The analysis detected the presence of two major functional categories, genes involved in brain development and starch metabolism.

Breaking down starch would have been advantageous for dogs’ ancestors in scavenging on early farmers’ discarded wheat and crop products.

“Wolves also have these genes but they don’t use them as efficiently as dogs,” Dr Axelsson continued.

“When we look at the wolf genome, we only see one copy of the gene [for the amylase enzyme] on each chromosome. When we look at the dog genome, we see a range from two to 15 copies – and on average a dog carries seven copies more than the wolf.

“That means the dog is a lot more efficient at making use of the nutrition in starch than the wolf.”

These differences, therefore, reflect the behavioural differences between dogs and wolves today.

“Previous experiments have indicated that when you select for a reduction in aggressiveness, you obviously get a tamer animal but you also get an animal that retains juvenile characteristics much longer during development, sometimes into adulthood,” said Dr Axelsson.

Dr Axelsson’s final theory may go some way to explaining the popular observation that dogs are permanently stuck in a kind of puppyhood.

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