What is the significance of the nine to three to three to one ratio in the second generation of a dihybrid cross?
Answer and explanation
Correct answer: It shows independent assortment
A dihybrid cross follows two pairs of contrasting traits at the same time. When the allele pairs assort independently, a cross such as AaBb × AaBb produces the F2 phenotypic ratio 9:3:3:1: nine with both dominant traits, three with the first dominant and second recessive, three with the first recessive and second dominant, and one with both recessive. Thus C is correct; the ratio does not prove acquired inheritance, linkage, or only sex determination.
Frequently asked questions
What is the correct answer to this question?
It shows independent assortment
Why is this the correct answer?
A dihybrid cross follows two pairs of contrasting traits at the same time. When the allele pairs assort independently, a cross such as AaBb × AaBb produces the F2 phenotypic ratio 9:3:3:1: nine with both dominant traits, three with the first dominant and second recessive, three with the first recessive and second dominant, and one with both recessive. Thus C is correct; the ratio does not prove acquired inheritance, linkage, or only sex determination.
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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