Explain Mendel's Law of Independent Assortment with the help of a dihybrid cross. Show the phenotypic and genotypic ratios obtained in the F2 generation.

Q: Explain Mendel's Law of Independent Assortment with the help of a dihybrid cross. Show the phenotypic and genotypic ratios obtained in the F2 generation.

Introduction to Mendel's Law of Independent Assortment\nMendel's Law of Independent Assortment is the third principal law of inheritance proposed by Gregor Mendel. It states that when two pairs of traits are combined in a hybrid, segregation of one pair of characters is independent of the other pair of characters at the time of gamete formation. Explanation through Dihybrid Cross\nTo understand this law, Mendel conducted dihybrid cross experiments by crossing pea plants with two contrasting pairs of characters. For example, he crossed a plant with round and yellow seeds (RRYY) with a plant having wrinkled and green seeds (rryy). Parent Generation (P): Round Yellow (RRYY) $\times$ Wrinkled Green (rryy) Gametes from Parents: RY and ry F1 Generation: All offspring were round and yellow (RrYy), showing that round and yellow are dominant traits. Selfing of F1 Generation\nWhen the F1 generation plants (RrYy) were self-pollinated, they produced four types of gametes in equal proportions: RY, Ry, rY, and ry. F2 Generation Phenotypic Ratio\nBy combining these gametes in a Punnett square (16-box grid), the F2 generation yielded four distinct phenotypes in a classic dihybrid ratio: Round and Yellow: 9 Round and Green: 3 Wrinkled and Yellow: 3 Wrinkled and Green: 1 \nThus, the phenotypic ratio is 9 : 3 : 3 : 1. Conclusion\nThe appearance of new combinations (Round-Green and Wrinkled-Yellow) in the F2 generation clearly indicates that the genes for seed shape and seed color assorted independently of each other during gamete formation. This forms the fundamental basis of genetic diversity in sexually reproducing organisms.

Question

Accepted Answer

Introduction to Mendel's Law of Independent Assortment
Mendel's Law of Independent Assortment is the third principal law of inheritance proposed by Gregor Mendel. It states that when two pairs of traits are combined in a hybrid, segregation of one pair of characters is independent of the other pair of characters at the time of gamete formation. Explanation through Dihybrid Cross
To understand this law, Mendel conducted dihybrid cross experiments by crossing pea plants with two contrasting pairs of characters. For example, he crossed a plant with round and yellow seeds (RRYY) with a plant having wrinkled and green seeds (rryy). Parent Generation (P): Round Yellow (RRYY) $	imes$ Wrinkled Green (rryy) Gametes from Parents: RY and ry F1 Generation: All offspring were round and yellow (RrYy), showing that round and yellow are dominant traits. Selfing of F1 Generation
When the F1 generation plants (RrYy) were self-pollinated, they produced four types of gametes in equal proportions: RY, Ry, rY, and ry. F2 Generation Phenotypic Ratio
By combining these gametes in a Punnett square (16-box grid), the F2 generation yielded four distinct phenotypes in a classic dihybrid ratio: Round and Yellow: 9 Round and Green: 3 Wrinkled and Yellow: 3 Wrinkled and Green: 1 
Thus, the phenotypic ratio is 9 : 3 : 3 : 1. Conclusion
The appearance of new combinations (Round-Green and Wrinkled-Yellow) in the F2 generation clearly indicates that the genes for seed shape and seed color assorted independently of each other during gamete formation. This forms the fundamental basis of genetic diversity in sexually reproducing organisms.

MP Board · Class 10 · Science · Heredity and EvolutionExplain Mendel's Law of Independent Assortment with the help of a dihybrid cross. Show the phenotypic and genotypic ratios obtained in the F2 generation.

Explanation through Dihybrid Cross\nTo understand this law, Mendel conducted dihybrid cross experiments by crossing pea plants with two contrasting pairs of characters. For example, he crossed a plant with round and yellow seeds (RRYY) with a plant having wrinkled and green seeds (rryy).

Selfing of F1 Generation\nWhen the F1 generation plants (RrYy) were self-pollinated, they produced four types of gametes in equal proportions: RY, Ry, rY, and ry.

F2 Generation Phenotypic Ratio\nBy combining these gametes in a Punnett square (16-box grid), the F2 generation yielded four distinct phenotypes in a classic dihybrid ratio: