 Labrador colouration is controlled by multiple genes . It is possible for recessive genes to re @-@ emerge in later generations . Also , there can sometimes be unexpected pigmentation effects to different parts of the body . Pigmentation effects appear in regard to yellow Labradors , and sometimes chocolate , and hence the majority of this section covers pigmentation within the yellow Labrador . The most common places where pigmentation is visible are the nose , lips , gums , feet , tail , and the rims of the eyes , which may be black , brown , light yellow @-@ brown ( " liver " , caused by having two genes for chocolate ) , or several other colours . A Labrador can carry genes for a different colour , for example a black Labrador can carry recessive chocolate and yellow genes , and a yellow Labrador can carry recessive genes for the other two colours . DNA testing can reveal some aspects of these . Less common pigmentations ( other than pink ) are a fault , not a disqualification , and hence such dogs are still permitted to be shown . 
