KITLG and obesity due to melanocortin 4 receptor deficiency: These include the fat-mass and obesity (FTO) gene which is strongly linked to body-weight traits in humans and cattle19, two genes (KITLG and ASIP) commonly linked to pigmentation/coat colour (see below), GHR, which has been linked to various phenotypes including milk composition in cattle20 and birth weight in humans21, and HMGA2, which has been associated with stature in both cattle22 and humans23.