Domestic animals’ cuteness and humans’ relatively flat faces may be the work of a gene that controls some important developmental cells, a study of lab-grown human cells suggests.
Some scientists are touting the finding as the first real genetic evidence for two theories about domestication. One of those ideas is that humans domesticated themselves over many generations, by weeding out hotheads in favor of the friendly and cooperative (SN: 7/6/17). As people supposedly selected among themselves for tameness traits, other genetic changes occurred that resulted in humans, like other domesticated animals, having a different appearance than their predecessors. Human faces are smaller, flatter and have less prominent brow ridges than Neandertal faces did, for instance.
Domesticated animals look different from their wild counterparts as well. Shorter snouts, curly tails, floppy ears and spotted coats are all traits that tend to pop up in domesticated animals. But until recently, no one had an explanation for this “domestication syndrome.”
Then in 2014, three scientists proposed that as people selected animals for tameness, they also happened to select for genetic changes that slightly hamper movement of some developmentally important cells (SN: 7/14/14). These neural crest cells are present early in embryonic development and migrate to different parts of the embryo where they give rise to many tissues, including bones and cartilage in the face, smooth muscles, adrenal glands, pigment cells and parts of the nervous system. The researchers’ idea was that mild genetic changes might produce neural crest cells that don’t move as well, leading to domestic animals’ cuddlier look.