In a dihybrid cross, what idea is supported by the 9:3:3:1 result?
Answer and explanation
Correct answer: Alleles for two different traits can assort independently.
A dihybrid cross follows two pairs of contrasting traits at the same time. In the classic cross RrYy × RrYy, independent assortment produces four equally likely gamete types, and their combinations give the F2 phenotypic ratio 9:3:3:1. This pattern indicates that the allele pair for one trait can separate independently of the allele pair for the other, under the conditions of Mendel’s model. Thus option A is correct.
Frequently asked questions
What is the correct answer to this question?
Alleles for two different traits can assort independently.
Why is this the correct answer?
A dihybrid cross follows two pairs of contrasting traits at the same time. In the classic cross RrYy × RrYy, independent assortment produces four equally likely gamete types, and their combinations give the F2 phenotypic ratio 9:3:3:1. This pattern indicates that the allele pair for one trait can separate independently of the allele pair for the other, under the conditions of Mendel’s model. Thus option A is correct.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: World of Living. Topic: Heredity and Evolution.
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