Why inheritance of colour blindness is an example of criss-cross inheritance?
Gene for colour blindness is located on X chromosome. The son can get it from the otherwise normal but carrier mother (XXo) and a colour blind (XoY) father can pass it on to his daughter. Thus this trait is passed to son from carrier mother and to daughter from colour blind father. Therefore, inheritance of colour blindness is an example of criss-cross inheritance.
(Xo- recessive allele bearing chromosome)