Question

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Explanation:

Analyze the question and options

The question asks for the genotype of a fourth-generation female cheetah based on her parents' genetic combinations. Although Figure 3 is not visible, we can evaluate the logical consistency of the multiple-choice options using principles of Genetic Inheritance.

Evaluate Option 1

"It must be strictly AA since she has to inherit both dominant alleles from each parent."
An offspring inherits one allele from each parent, not both from each. Thus, this statement is biologically incorrect.

Evaluate Option 2

"It could be AA or Aa since she can inherit a dominant or recessive allele from the remaining parent."
This describes a scenario where one parent must pass a dominant allele (\(A\)), while the other parent can pass either a dominant (\(A\)) or recessive (\(a\)) allele. This is a common genetic outcome.

Evaluate Option 3

"It could be Aa or aa since she must inherit a recessive allele from at least one of her parents."
This describes a scenario where at least one parent is homozygous recessive (\(aa\)), forcing the offspring to inherit at least one recessive allele (\(a\)).

Evaluate Option 4

"It must be strictly Aa since she will inherit both a dominant and recessive allele from each parent."
An offspring only inherits one allele per gene from each parent, making it impossible to inherit both a dominant and a recessive allele from a single parent.

Determine the correct choice

By analyzing the phrasing of the options:

• Option 3 states she must inherit a recessive allele from at least one parent, which would limit her genotype to \(Aa\) or \(aa\).
• Option 2 states she can inherit a dominant or recessive allele from the remaining parent, leading to \(AA\) or \(Aa\).

In typical pedigree problems involving rare recessive traits, affected individuals are \(aa\) and unaffected carriers are \(Aa\). If a parent is \(aa\), any offspring must receive at least one \(a\) allele, meaning their genotype could be \(Aa\) or \(aa\) depending on the other parent. Option 3 provides a logically complete genetic explanation of inheritance rules.

Answer:

• It must be strictly AA since she has to inherit both dominant alleles from each parent.
• It could be AA or Aa since she can inherit a dominant or recessive allele from the remaining parent.
• It could be Aa or aa since she must inherit a recessive allele from at least one of her parents. (Correct answer)
• It must be strictly Aa since she will inherit both a dominant and recessive allele from each parent.