Question

If a cross between two individuals produces offspring with 50% dominant character (A) and 50% recessive character (a) then the Genotypes of parents are:

Options

• Aa × Aa

• Aa × aa

• AA × aa

• AA × Aa

Answer 1

Aa × aa

Explanation:

To have 50% dominant and 50% recessive offspring, one parent must be homozygous recessive (aa) and the other must be heterozygous dominant (Aa). A cross of Aa and Aa yields 1 AA : 2 Aa : 1 aa. All dominant children result from a cross between two pure breeding dominant (AA) and recessive (aa) parents. In a 1 : 1 ratio, homozygous dominant (AA) and heterozygous dominant (Aa) parents produce homozygous and heterozygous dominant kids.