Question

if aa, aa, and aa are the possible genotypes of the offspring in a cross, then what are the parent genotypes? a aa and aa b aa and aa c aa and aa d aa and aa

Explanation:

Step1: Analyze option a

When \(Aa\times Aa\), using Punnett square:

Gametes of first parent	Gametes of second parent
\(A\)	\(a\)
\(a\)	\(A\)
\(a\)	\(a\)

The genotypes of offspring are \(AA:Aa:aa = 1:2:1\)

Step2: Analyze option b

When \(AA\times Aa\), using Punnett square:

Gametes of first parent	Gametes of second parent
\(A\)	\(a\)

The genotypes of offspring are \(AA:Aa=1:1\)

Step3: Analyze option c

When \(Aa\times aa\), using Punnett square:

Gametes of first parent	Gametes of second parent
\(a\)	\(a\)

The genotypes of offspring are \(Aa:aa = 1:1\)

Step4: Analyze option d

When \(AA\times AA\), using Punnett square:

Gametes of first parent	Gametes of second parent

The genotype of offspring is \(AA\)

Answer:

A. Aa and Aa