|Photo Brian Hare/Duke University|
This was also confirmed by the Silver Fox project. While the foxes were solely bread for behavioral traits, changes in physical features followed hand in hand.
Why would that happen?
A new hypothesis has been proposed which could explain why breeding for tameness would result in increased cuteness at the same time, so called domestication syndrome. The domestication syndrome is the oldest nut to be cracked.
It has been suggested that the underlying link is the group of embryonic stem cells called the neural crest.
"The neural crest hypothesis neatly ties together this hodge-podge of traits."Neural crest cells are formed near the developing spinal cord of early vertebrate embryos. As the embryo matures, the cells migrate to different parts of the body and give rise to many tissue types including pigment cells and parts of the skull, jaws, teeth, ears, as well as the adrenal glands and indirectly involved in brain development.
Breading animals for tameness might have inadvertently cause selection for mild neural crest deficits, resulting in less fearful animals.
Domestication syndrome: White patches, baby faces and tameness explained by mild neural crest deficits