From wolf to dog: Behavioural evolution during domestication

Domestication is a process in which species are selected to live in human-controlled environments (Price 2002). The evolutionary trajectories of numerous animal and plant species has dramatically impacted by domestication, and the process thus provides an ideal framework for studying evolutionary responses to selection (Driscoll et al. 2009). In some of his most influential work, Darwin (1859; 1868) used domestication as a powerful exemplification of how various traits can be modified by selection. There are numerous examples of how artificial human-induced selection pressures exerted during domestication affects the same traits across a wide range of species (Darwin 1868; Brown et al. 2009; Trut et al. 2009; Wilkins et al. 2014). Specifically, compared to their wild counterparts domesticated animals typically express repeated patterns of altered physiology, morphology and behaviour, a phenomenon known as the "domestication syndrome" (Darwin 1868; Hammer 1984). For example, domesticated mammals commonly express increased tameness, reduced brain size, depigmentation, floppy ears, curly tails and changes in hormonal profiles (Driscoll et al. 2009; Sánchez-Villagra et al. 2016, Figure 1). The repeated occurrence of suites of traits across a wide range of domesticated species seems unlikely to be caused by unique mutations, but rather to be a result of correlated traits driven by altered selection pressures during domestication (Trut 1999; Trut et al. 2009)...........