What is the law of independent assortment? Explain with an example? (AS1)

When there are two pairs of contrasting character, the distribution of the members of one pair into the gametes is independent of the distribution of the other pair as seen in the production of gametes of the first filial generation. For example: When a pea plant with yellow and round seeds (pure), were crossed with those having green and wrinkled seeds (pure). The F1 seeds were obtained yellow and round. When these F1 seeds were grown in plants, F2 seeds were obtained which showed all the four possible combinations i.e., yellow and round, yellow and wrinkled, green and round, green and wrinkled. These four kinds of seeds were obtained in the ratio of 9:3:3:1. The above results would be expected if the two pairs of characters are believed to behave independently of each other. Therefore, it can be concluded that the two characters under considerations are assorting in an independent fashion. The independent assortment holds good for two or more than two pairs of characters.