Question

What is the genotypic ratio in the F₂ generation from a dihybrid cross?

Options

• 3:1

• 9:3:3:1

• 1:2:1:2:4:2:1:2:1

• 1:2:2:4:1:2:1:2:1

Answer 1

The F₂ genotypic ratio is 1:2:2:4:1:2:1:2:1, representing the nine distinct genotype classes. The four-copy class (RrYy) is the most frequent, appearing four times. Single-copy classes include homozygous combinations like RRYY and rryy.