Question

In which crosses both phenotypic and genotypic F$_2$ ratios are 1:2:1?

I) Red $\times$ White snapdragon (incomplete dominance)
II) Tall $\times$ Dwarf garden pea
III) Dotted $\times$ Spotted seed coat lentil
IV) Homozygous $\times$ Heterozygous

• A. I, II
• B. III, IV
• C. I, III
• D. II, III

Hint:

1:2:1 phenotypic + genotypic ratio is characteristic of incomplete or codominance.

Answer 1

The Correct Option is C

- I: Incomplete dominance (e.g., Snapdragon) – Both phenotype and genotype show 1:2:1.
- III: Codominance (e.g., Seed coat in lentil) – Shows 1:2:1 in both.
- II and IV: Show classic 3:1 phenotype, 1:2:1 genotype, but not both.