2 Phenotypic change under domestication

2.1 Introduction

For centuries, livestock breeders have nurtured strains of animals that thrive on various diets or in particular climates, or that excel in certain roles or simply please their fancy. The variety of such animals seems bewildering but certain changes consistently emerge in a surprisingly wide range of domesticated species and among humans, suggesting that similar mechanisms are operating. Here we describe just two such clusters of changes, in the skeleton and in the skin.