“l’heure entre chien et loup”, “the hour between dog and wolf”. This french phrase is used when two things can't be easily distinguished from each other because they are so alike. As the phrase indicates, the difference between a dog and a wolf is so subtle. But why is it so? It is because the dog (Canis Familiaris) is a descendant of the Grey Wolf (Canis Lupus). Dogs and wolves were the same species decades ago, but they are not these days.
Evolutionary Aspect
When we say two organisms belong to the same species, the organisms can interbreed to produce fertile offspring. Dogs and wolves can interbreed with one another to produce viable, fertile offspring. However, interbreeds do not occur frequently due to barriers because their behaviors, and instincts became divergent. Firstly, hunting strategies. Wolves hunt for food nowadays, while most dogs do not. Few dogs hunt for food. A bulk of dogs just get food from their owners. Their hunting instincts and skills are mostly gone since their need for hunting has disappeared. In the natural world, it is common for wolves with similar hunting and foraging strategies to mate and teach these strategies to their offspring. Consequently, these variations led to a decrease in the number of interbreeding between wolves and dogs.
Photo credit : Phys.org
By now, you might have a question about how dogs evolved from wolves in the first place. At first, artificial selection (domestication in this case) by humans took place. Domestication is “the process of adapting wild plants and animals for human use, and dogs fit their needs”. One day, archaic humans realized that dogs are helpful in guarding, hunting, and other tasks. From then, humans fed them and gave them safe places for them to stay in order to domesticate them. The domestication of wolves brought benefits to both sides. From the point of view of wolves, they could easily get more available food from humans and shelter, and that increased their survival and fitness.
Photo Credit : Khan Academy
Genetic Aspect
Wolves and Dogs began to genetically diverge from each other between 40,000 and 27,000 years ago. One example of genetic divergence is the Amy2B genes. Amy2B gene codes for pancreatic amylase. The pancreas and salivary glands produce the amylase enzyme, which facilitates the body’s breakdown of carbohydrates. As the domestication of wolves occurred and as the dogs dwelled with humans, especially within farming communities, there was a high possibility of dogs getting starchy diets. Due to this variation in diets (environmental pressure), dogs went through starch diet adaptation. That adaptation resulted in more copy numbers of the gene Amy2B in dogs than those in wolves.
References
Arendt, M. (2016, July 13). Diet adaptation in dog reflects spread of prehistoric agriculture. Nature. https://www.nature.com/articles/hdy201648?error=cookies_not_supported&code=c7fb3e0d-2605-44e5-bf37-1629e721ecc2
domestication | National Geographic Society. (n.d.). Retrieved November 7, 2022, from https://education.nationalgeographic.org/resource/domestication/
Eons, P. (2020a, March 31). How Dogs (Eventually) Became Our Best Friends. YouTube. https://www.youtube.com/watch?v=nDt0HKSdRRw&feature=youtu.be
Murugesu, J. A. (2022, July 5). Dogs are descended from two populations of ancient wolves. New Scientist. https://www.newscientist.com/article/2326717-dogs-are-descended-from-two-populations-of-ancient-wolves/
Ollivier, M., Tresset, A., Bastian, F., Lagoutte, L., Axelsson, E., Arendt, M. L., Bălăşescu, A., Marshour, M., Sablin, M. V., Salanova, L., Vigne, J. D., Hitte, C., & Hänni, C. (2016). Amy2B copy number variation reveals starch diet adaptations in ancient European dogs. Royal Society Open Science, 3(11), 160449. https://doi.org/10.1098/rsos.160449
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