Genetics and the Behavior of Domestic Animals

In this chapter, we begin by defining domestication as a genetic process, whereby animals change phenotypically and genetically as a response to living under human supervision. This has caused a convergent set of phenotypic modifications across numerous different species, through a combination of relaxed natural selection, increased human selection, and correlated responses. The genetic mechanisms underlying these processes are discussed in addition to genetic drift and inbreeding. The driving types of mutations are dealt with, as is the way in which genes are organized in the genome to give rise to a specific genetic architecture facilitating selection responses. The different methods used to discover genes and mutations are divided into either top-down approaches, where one starts with the phenotype and uses mapping methods to find the causative genes, or bottom-up, where the genetic polymorphism is the starting point and the phenotype the desired response variable. A number of examples of single genes and mutations that have been coupled to behavioral variation are given, among them genes showing pleiotropic effects on pigmentation, and genes involved in regulation of the effects of neuropeptides. Finally, the relatively novel area of behavioral epigenetics is examined, in particular with its possible relation to domestication effects.