In the F2 generation of a dihybrid cross two phenotypes appear in the ratio 1:1. two phenotypes appear in the ratio 3:1. four phenotypes appear in the ratio 12:4. four phenotypes appear in the ratio 9:3:3:1. three phenotypes appear in the ratio 1:2:1.

four phenotypes appear in the ratio 9:3:3:1

Explanation:

For a dihybrid cross in which the two genes concerned obey simple dominant/recessive law and are independently assorting, four phenotypes are produced in the ratio 9:3:3:1.

The dominant gene takes up the largest ratio (9/16) while the recessive gene takes up the smallest (1/16). Any deviation from 9:3:3:1 and the number of phenotypes produced from a dihybrid cross is an indication that the genes involved do not obey Mendelian laws.

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