Small dog breeds are not made by humans

It has long been thought that small dog breeds, such as Chihuahuas or dwarf spitz (also called “Pomeranian cuties”), appeared after the domestication of dogs by people, the latter wanting to surround themselves with beautiful which are small partners. . But recent work published in Current Biology shows that, on the contrary, small dogs would have appeared before the action of Man of this kind. For more than 10 years, a French specialist in the subject, geneticist Jocelyn Plassais, has been working on a genetic mutation that affects a growth hormone in dogs. However, this mutation found in small dogs already existed in wolves over 50,000 years ago, before domestication.

To understand the stakes of this discovery, we need to go back to the history of canids. The wolf (Canis lupus), would have appeared about 1.5 million years ago, after splitting from the coyote branch (Canis latrans) lives in North America. The appearance of the dog is the result of the domestication of the wolf, about 15,000 to 30,000 years ago. “It is believed that the first dogs made it possible to protect Man against other wild animals, perhaps also to help in hunting. Regarding the size of the dogs, the first “wolf-dogs” must have been the same size as the wild wolves of that time, weighing more than 25 to 35 kg.“, explained Jocelyn Plassais sa Science and the Future. “It is also possible that the first “wolf dogs” found it useful to rub shoulders with people who did not live with them, for example to have access to leftover food. As a result, they become closer and closer to Men to eventually live and become domesticated. But it’s still a guess..” Afterwards, almost all current varieties were created in the 18th and 19th centuries, thanks to the powerful selection of people. Today, there are over 350 dog breeds worldwide.

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