Along with the majority of our customers and Field Reps, I consider companion
animals as family members. I believe that their diets should be as healthy and delicious
as our own, which is why I have dedicated my life to researching the best foods
and products for our pet kids. Although there are significant differences in nutritional
requirements and taste preferences between dogs and humans, new compelling research
published this year suggests that canine diets, and subsequent genetic profiles,
evolved in order to cohabitate with humans.
Part of the ancient mystery of the makeup of the modern canine has been solved by
a team led by researchers at the University of California, Davis, School of Veterinary
Medicine and evolutionary geneticist Erik Axelsson of Uppsala University and his
colleagues in Sweden.
The study published in Nature by Erik Axelsson (et. al.) analyzed genes related
to starch digestion in domesticated canines and their ancestors, wild wolves. The
research hypothesized that when humans transitioned from a nomadic hunter-gatherer
lifestyle to settled farming communities, wolves gave up their meat-only diets to
scavenge convenient, carbohydrate-rich food from human scrap piles. Animals that
could best make use of the new starchy food source developed an evolutionary advantage
and gradually morphed over many generations into man’s best friend.
The Swedish study focused on genetic differences between 60 dogs representing
14 breeds and 12 wolves from around the world. Those changes, the researchers reasoned,
could identify genes that were important in separating dogs from wolves.
The researchers determined the genetic makeup of groups of dogs and compared
the results to those from wolves, concentrating on parts of the genetic instruction
book that differ between the two species. The search revealed substantial numbers
of genes involved in starch digestion and metabolism, and in the utilization of
fats. The team also found that, compared to wolves, canines have more copies of
a gene that produces an enzyme that breaks starch into easily digestible sugars.
Other genetic variants seem to contribute to dogs’ increased ability to convert
a sugar called maltose to glucose, the sugar that cells prefer to burn for energy,
and yet other genetic changes improve dogs’ ability to move glucose into their cells.
Combined, the mutations alter dogs’ metabolism so they can get more energy out of
a carbohydrate-rich diet than wolves can, and the scientists confirmed the effect
of the genetic variants by identifying biochemical differences in starch metabolism
in blood and tissue samples from dogs and wolves, showing that in comparison to
wolves, dogs have a profound adaption to utilize carbohydrates.
In addition to the Swedish study, a research group from the Canid Diversity and
Conservation Group in the Veterinary Genetics Laboratory at the UC Davis School
traced back when dogs developed distinct starch-digestion genetic mutations.
Several thousand years after dogs originated in the Middle East and Europe, some
of them moved south with ancient farmers. Now separated by vast distances from native
wolf populations, these early companion animals developed a distinct genetic profile,
now reflected in today’s canines. To calculate when this happened, the researchers
calculated the mutation rate of genetic markers on the Y chromosome in a sample
of 100 Australian dingoes, a dog population known to have appeared about 4,200 years
ago. Knowing the rate at which these genetic mutations occur, the researchers were
able to backtrack through history and estimate the point when wolves and dogs diverted
paths at roughly 7,000 years ago. These findings, based on the rate of genetic marker
mutations in the dog’s Y chromosome, supply the missing piece of the puzzle as to
when ancient dogs ventured beyond Southeast Asia. The study results are published
in the Journal of Molecular Biology and Evolution.
Both studies fit together nicely, and confirm what I have always strongly suspected:
dogs are not wolves. Plus, now I know that there is an evolutionary explanation
for why my dog Otto was always so jealous of my breakfast pastries!
Thank you for all you do to make the world a better place for companion animals.
Dr. Jane Bicks