In a monohybrid cross, what does the 3:1 ratio in the second generation prove?
Answer and explanation
Correct answer: Alleles for a trait segregate and can recombine in new combinations.
The 3:1 phenotypic ratio in the F2 generation is characteristic of a monohybrid cross between two heterozygotes, such as Tt × Tt. The alleles separate when gametes form, and fertilisation recombines them. The genotypic ratio is 1 TT:2 Tt:1 tt, which produces a 3 tall:1 dwarf phenotype ratio when T is dominant. Hence option A is correct; recessive alleles are hidden, not erased.
Frequently asked questions
What is the correct answer to this question?
Alleles for a trait segregate and can recombine in new combinations.
Why is this the correct answer?
The 3:1 phenotypic ratio in the F2 generation is characteristic of a monohybrid cross between two heterozygotes, such as Tt × Tt. The alleles separate when gametes form, and fertilisation recombines them. The genotypic ratio is 1 TT:2 Tt:1 tt, which produces a 3 tall:1 dwarf phenotype ratio when T is dominant. Hence option A is correct; recessive alleles are hidden, not erased.
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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