ICSE Class 10 Answered
The law of segregation explains monohybrid cross. It states that, ‘The characteristics or traits of an organism are determined by internal “factors” which occur in pairs. Only one of a pair of such factors can be present in a single gamete.’
The law of independent assortment explains dihybrid cross. It states that, ‘In the inheritance of more than one pair of traits in a cross simultaneously, the factors responsible for each pair of traits are distributed independently to the gametes.’
Criss-cross inheritance: Inheritance of X linked genes, as in colour blindness and haemophilia, is also called criss-cross inheritance. This is because the defective gene is passed on from one sex to the opposite sex of the next generation. The colourblind son of the family may receive the defective gene from his mother, who is otherwise normal, but is a carrier. The colourblind daughter of the family may receive the defective gene from her colourblind father, provided the mother is a carrier.