Question

In an experiment to study independent inheritance of two separate traits: shape and colour of seeds, the ratio of the different combinations in F₂ progeny would be

• A. 1 : 3
• B. 1 : 2 : 1
• C. 9 : 3 : 3 : 1
• D. 9 : 1 : 1 : 3

Answer 1

The Correct Option is C

Step 1: Understanding the Experiment:
The experiment mentioned involves studying the independent inheritance of two separate traits: the shape and color of seeds. According to Gregor Mendel's laws of inheritance, traits assort independently in F₂ progeny if they are controlled by different gene pairs located on different chromosomes.

Step 2: Mendel's Law of Independent Assortment:
According to the law of independent assortment, genes for different traits segregate independently during the formation of gametes. When two heterozygous pea plants are crossed (e.g., both being TtYy for seed shape and color, where T is for tall, t is for dwarf, Y is for yellow, and y is for green), the resulting F₂ progeny will exhibit a 9:3:3:1 phenotypic ratio.
- 9 represent the offspring with both dominant traits (e.g., round and yellow seeds).
- 3 represent the offspring with one dominant and one recessive trait (e.g., round and green seeds or wrinkled and yellow seeds).
- 3 represent the offspring with the other dominant and recessive trait (e.g., wrinkled and green seeds).
- 1 represents the offspring with both recessive traits (e.g., wrinkled and green seeds).

Step 3: Conclusion:
The ratio of the different combinations of seed shape and color in the F₂ progeny would be 9:3:3:1, as per Mendel's law of independent assortment.