Domesticated animals generally share a common set of traits that set them apart from their wild counterparts, including curly tails, floppy ears, smaller brains, and smaller teeth. This phenomenon is called “domestication syndrome,” and scientists and geneticists have posited several reasons why this may occur.
Adam Wilkins and his colleagues at the Stellenbosch Institute of Advanced Study posit human selection has caused alteration of an organ system present during embryonic development called the neural crest. Neural crest cells form near the spinal cord during fetal development and travel up to various parts of the body, pigmenting parts of the skull, jaws, teeth, and ears. The neural crest cells also play a part in developing the adrenal glands, responsible for “fight or flight” syndrome.
Humans looking for friendlier, calmer pets may have inadvertently bred animals with mild neural crest cell deficiencies. In addition to being less fearful because of the adrenal development effects of this deficit, these animals show other effects of neural crest shortage: malformed ear cartilage (floppy ears), tooth anomalies, and jaw development changes.
Animal domestication has been a crucial and fascinating part of human civilization, and scientists are getting closer to a more complete understanding of the matter. Think about that next time you look at your dog, and read on by following the links below!
Sources:
http://www.sciencedaily.com/releases/2014/07/140714100122.htm
http://www.iflscience.com/plants-and-animals/why-so-many-domesticated-mammals-have-floppy-ears
