The domestication of dogs was not only a social and behavioral process but also a dietary one. While wolves primarily consumed meat, domestic dogs adapted to human-provided food, which often included starch-rich agricultural products. The 2016 PLoS ONE study explored this adaptation by analyzing copy number variations in three metabolic genes: GCKR (sugar metabolism), PHYH (meat metabolism), and AMY2B (starch metabolism).
The researchers found no significant dietary correlation with GCKR or PHYH, but AMY2B showed a clear expansion in copy number. This increase was not limited to early domestication; positive selection continued in dog breeds exposed to starch-heavy diets well after the initial dog–wolf split. Importantly, the study also confirmed that wolf introgression was not responsible for variation in AMY2B selection, strengthening the case for an independent, diet-driven adaptation in domestic dogs.
These findings support the hypothesis that amylase gene expansion is universal across dogs and represents one of the most striking genetic examples of co-evolution with humans. By aligning with human agricultural practices, dogs enhanced their ability to thrive on starch-based foods, underscoring the deep nutritional and evolutionary partnership between species.
Ultimately, the study illustrates how human influence shaped not only the behavior and appearance of dogs but also their genetic capacity to process food, forging a biological bond rooted in shared diets and survival strategies.
Source: Dietary Variation and Evolution of Gene Copy Number among Dog Breeds. (2016). PLoS ONE, 11. https://doi.org/10.1371/journal.pone.0148899
