Breeding for tameness tends to produce animals with floppy ears, patches of white fur, juvenile faces, small jaws and other features, a new study reports.
Authors of the paper, published in the journal Genetics, believe the suite of features are tied to what they call "domestication syndrome," which can apply not only to mammals like dogs, foxes, pigs, horses, sheep and rabbits, but also to domesticated birds and fish, even if the latter two groups don't display all of the anatomical changes associated with tame mammals.
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The researchers theorize that domestication with tameness as a goal leads to genetic alterations that can affect a group of embryonic stem cells called the neural crest. Scientists, including Charles Darwin, have been wondering why domesticated animals seem to have so many features and behaviors in common.
"Because Darwin made his observations just as the science of genetics was beginning, the domestication syndrome is one of the oldest problems in the field," co-author Adam Wilkins from the Humboldt University of Berlin said in a press release. "So it was tremendously exciting when we realized that the neural crest hypothesis neatly ties together this hodge-podge of traits."