Ancient dog breed DNA helps unravel clues about evolution of man’s best friend

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An international study led by UNSW researchers has mapped one of the most intact and complete dog genomes ever generated.

The genome sequence of the basenji dog (Canis lupus familiaris) could have a big impact on the understanding of dog evolution, domestication and canine genetic diseases.

The basenji—also known as the barkless dog—is an ancient African dog breed which still lives and hunts with tribesmen in the African Congo. 

In the study—published in BMC Genomics—the researchers say the genome of the basenji, which sits at the base of the dog breed family tree, makes an excellent unbiased reference for future comparisons between dog breeds and evolutionary analysis of dogs.

“The dog was probably the first animal to be domesticated by humans and has subsequently been artificially selected by humans into a great diversity of dog breeds of different sizes and shapes,” lead author of the study and senior lecturer in Genomics and Bioinformatics at UNSW Sydney’s School of Biotechnology and Biomolecular Sciences, Dr Richard Edwards said. 

“Before this paper, it was difficult to interpret differences between the dog reference genomes and non-domesticated dogs, such as dingoes, jackals, coyotes, wolves and foxes. Big changes could be the result of recent artificial selection during creation of the specific reference breed. 

“By adding such a high-quality genome at the base of the domestic dog family tree, we have provided an anchor point for studies that can help establish the timing and direction of genetic changes during domestication and subsequent breeding.”

The basenji genome sequence is different to the traditional dog reference genome, CanFam, which is of a highly-derived breed, the boxer. The choice of dog reference genome can affect the results of future dog genetics studies looking at genetic variants. 

“For example, the boxer is much more closely related to other mastiffs than other breeds,” Dr Edwards said. 

“This may introduce biases in genetic analyses across many dog breeds. There is also the risk that breed-specific variation may map poorly—or not at all—to a biased reference. In principle, the basenji is equally distant from most modern breeds, making it a less biased basis for comparisons.”

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