Question

What is the expected genotypic ratio when an F₁ heterozygous individual (Tt) is back crossed with the homozygous dominant parent (TT)?

Options

• TT : Tt (1:1)

• All TT

• Tt : tt (1:1)

• TT : Tt : tt (1:2:1)

Answer 1

When F₁ (Tt) is crossed with the homozygous dominant parent (TT), the cross Tt × TT produces offspring with genotypes TT and Tt in a 1:1 ratio. Both genotypes express the dominant phenotype, so all offspring appear tall or dominant.