Question

does alkaptonuria appear to be caused by a dominant allele or by a recessive allele?
dominant
recessive
previous answers
correct
part b
fill in the genotypes of the individuals whose genotypes can be deduced.
drag the appropriate labels to their respective targets. labels can be used once, more than once, or not at all.
aa
aa
aa
jorge
ariana
mariposa
benito
diego
elena
carmen
miguel
hector
julio
paloma
roberto
carlota
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you labeled 3 of 13 targets incorrectly.

Explanation:

Step1: Identify affected individuals (aa)

Individuals with alkaptonuria (shaded) have genotype $aa$: Ariana, Benito, Elena, Carlota.

Step2: Deduce carriers from affected parents

A child with $aa$ gets one $a$ from each parent.

• Jorge (parent of Elena, $aa$): must be $Aa$
• Carmen (parent of Carlota, $aa$): must be $Aa$
• Miguel (parent of Carlota, $aa$): must be $Aa$
• Mariposa (parent of Benito, $aa$): must be $Aa$

Step3: Deduce unaffected from affected parent

Affected parent ($aa$) passes $a$ to all children. Unaffected children get $A$ from other parent:

• Diego (child of Jorge $Aa$ + Ariana $aa$): $Aa$
• Carmen (child of Jorge $Aa$ + Ariana $aa$): $Aa$ (already confirmed)
• Hector (child of Mariposa $Aa$ + Benito $aa$): $Aa$
• Julio (child of Mariposa $Aa$ + Benito $aa$): $Aa$

Step4: Deduce unaffected from carrier parents

Julio $Aa$ + Paloma (unaffected, child of two unaffected parents with no affected children): Paloma is $AA$ or $Aa$; their child Roberto is unaffected, so he can be $AA$ or $Aa$, but since no affected siblings, we confirm:

• Paloma: $Aa$ (since Julio is $Aa$, and no affected children, but to be consistent with recessive inheritance, she is a carrier)
• Roberto: $AA$ or $Aa$, but most likely $Aa$ (but since he is unaffected, we can confirm $Aa$ as the only deducible carrier genotype, or $AA$ is possible, but based on pedigree, $Aa$ is correct)

Wait, correction: For Roberto, since both parents are $Aa$, he can be $AA$ or $Aa$, but since there's no affected sibling, we can't confirm $AA$, so the only deducible genotypes are based on affected individuals and their parents/children.

Answer:

• Ariana: $aa$
• Benito: $aa$
• Elena: $aa$
• Carlota: $aa$
• Jorge: $Aa$
• Mariposa: $Aa$
• Carmen: $Aa$
• Miguel: $Aa$
• Diego: $Aa$
• Hector: $Aa$
• Julio: $Aa$
• Paloma: $Aa$
• Roberto: $Aa$ (or $AA$, but $Aa$ is the confirmed carrier genotype based on parents)