Question

In a pea plant the gene T for tallness is dominant over the gene t for dwarfness. If two heterozygous individuals are crossed ______.

Options

• the phenotypic and the genotypic ratio will be the same.

• the genotypic ratio would be (3 : 1)

• the phenotypic ratio would be 3 dwarf : 1 tall

• (25%) individuals would be dwarf

Answer 1

In a pea plant the gene T for tallness is dominant over the gene t for dwarfness. If two heterozygous individuals are crossed (25%) individuals would be dwarf.

Explanation:

The cross is Tt × Tt, giving genotypes TT, Tt, Tt and tt. Thus, one-quarter of the offspring are dwarf (tt); the phenotypic ratio is 3 tall : 1 dwarf.