carnivore genetic divergence Victorian era selection phenotypic artificial selection poodle mastiff lncRNA IGF1 Victorian era dog phenotype
The domestic dog is the first species, and the only large carnivore, to have been domesticated. The first dogs were certainly wolflike, but the phenotypic changes that coincided with the dog–wolf genetic divergence are not known. Dogs are the most variable mammal on earth with around 450 globally recognized dog breeds. In the Victorian era, directed human selection developed the modern dog breeds, which resulted in a vast range of phenotypes. Most breeds were derived from small numbers of founders within the last 200 years, and since then dogs have undergone rapid phenotypic change and were formed into today's modern breeds due to artificial selection imposed by humans. These breeds can vary in size and weight from a 0.46 kg (1.0 lb) teacup poodle to a 90 kg (200 lb) giant mastiff. The skull, body, and limb proportions vary significantly between breeds, with dogs displaying more phenotypic diversity than can be found within the entire order of carnivores. These breeds possess distinct traits related to morphology, which include body size, skull shape, tail phenotype, fur type and colour. The difference in size has been attributed to a lncRNA variant in the IGF1 region arisen in wolves from northern latitudes c. 53.000 years ago and fixed by natural and subsequently by human selection. Their behavioral traits include guarding, herding, and hunting, retrieving, and scent detection. Their personality traits include hypersocial behavior, boldness, and aggression, which demonstrates the functional and behavioral diversity of dogs. As a result, today dogs are the most abundant carnivore species and are dispersed around the world. The most striking example of this dispersal is that of the numerous modern breeds of European lineage during the Victorian era.
