Domestication syndrome

Domestication syndrome refers to two sets of phenotypic traits that are common to either domesticated plants^[1][2] or domesticated animals.^[3]

Domesticated animals tend to be smaller and less aggressive than their wild counterparts, they may also have floppy ears, variations to coat color, a smaller brain, and a shorter muzzle. Other traits may include changes in the endocrine system and an extended breeding cycle.^[3][4][5] These animal traits have been claimed to emerge across the different species in response to selection for tameness, which was purportedly demonstrated in a famous Russian fox breeding experiment,^[6][7][8] though this claim has been disputed.^[9][10]

Other research^[3] suggested that pleiotropic change in neural crest cell regulating genes was the common cause of shared traits seen in many domesticated animal species. However, several recent publications have either questioned this neural crest cell explanation^[4][11][10] or cast doubt on the existence of domestication syndrome itself.^[9] One recent publication^[10] points out that shared selective regime changes following transition from wild to domestic environments are a more likely cause of any convergent traits. In addition, the sheer number, diversity, and phenotypic importance of neural crest cell-derived vertebrate features means that changes in genes associated with them are almost inevitable in response to any significant selective change.^[10]  

The process of plant domestication has produced changes in shattering/fruit abscission, shorter height, larger grain or fruit size, easier threshing, synchronous flowering, and increased yield, as well as changes in color, taste, and texture.^[12]