The law of dominance is not universally applicable.

Explanation

(1) There are many traits in many organisms which show dominance. For example, in guinea pigs black coat colour is dominant over white coat colour. Similarly, in human beings curly hair is dominant over straight hair and brown colour of eye is dominant over green or blue eye.
(2) However a number of cases have been reported where dominance is either incomplete or absent.
(3) The phenomenon of dominance is important as it makes the harmful recessive characters. For example, in human beings, haemophilia, a form of idiocy, diabetes, etc. are caused due to recessive genes.
(4) Thus, the law of dominance is not universally applicable.