Question

If a cross between two individuals produces offsprings with $50\%$ dominant character (A) and $50\%$ recessive character (a) the genotype of parents are

• A. $Aa\times Aa$
• B. $Aa\times aa$
• C. $AA\times aa$
• D. $AA\times Aa$

Answer 1

The correct option is B $Aa\times aa$

aa Aa	a
A	Aa (dominant)
a	aa (recessive)

To have 50% dominant and 50% recessive progeny one parent should be homozygous recessive (aa) and other should be heterozygous dominant (Aa). A cross between Aa and Aa gives 1 AA: 2 Aa : 1 aa. A cross between two pure breeding dominant (AA) and recessive (aa) parents give all dominant progeny. Homozygous dominant (AA) and heterozygous dominant (Aa) parents give homozygous and heterozygous dominant progeny in 1:1 ratio. Thus, the correct answer is option B.