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moving to the next question prevents changes to this answer. question 35 of 50
question 35
if a is dominant to a and b is dominant to b, what is the expected phenotypic ratio of the cross: aabb × aabb?

1. 16:0:0:0
2. 8:4:2:2
3. 9:1:1:3
4. 9:3:3:1

Explanation:

Step1: Determine gametes

For \(AaBb\), the possible gametes are \(AB\), \(Ab\), \(aB\), \(ab\)

Step2: Create Punnett square

	\(AB\)	\(Ab\)	\(aB\)	\(ab\)
\(Ab\)	\(AABb\)	\(AAbb\)	\(AaBb\)	\(Aabb\)
\(aB\)	\(AaBB\)	\(AaBb\)	\(aaBB\)	\(aaBb\)
\(ab\)	\(AaBb\)	\(Aabb\)	\(aaBb\)	\(aabb\)

Step3: Calculate phenotypes

• \(A - B-\) (both dominant): \(9\) ( \(AABB\), \(AABb\), \(AaBB\), \(AaBb\) )
• \(A - bb\) (only \(A\) dominant): \(3\) ( \(AAbb\), \(Aabb\) )
• \(aaB-\) (only \(B\) dominant): \(3\) ( \(aaBB\), \(aaBb\) )
• \(aabb\) (both recessive): \(1\)

Answer:

1. \(9:3:3:1\)