Question

1. having freckles is a dominant trait in humans. a girl has freckles, but her brother does not.

what genotypes could result in these children with different traits?
ff and ff
ff and ff
ff and ff
ff and ff

Explanation:

Step1: Analyze dominant and recessive traits

Let \(F\) represent the dominant allele (for freckles) and \(f\) represent the recessive allele (no freckles). A person with freckles can have genotypes \(FF\) or \(Ff\), while a person without freckles has genotype \(ff\).

Step2: Check each option

• Option 1 (\(FF\) and \(ff\)): If one child is \(FF\) (has freckles) and the other is \(ff\) (no freckles), but for two children to have these genotypes, parents' genotypes would have to be \(Ff\) and \(ff\) (not relevant as we are looking at children's genotypes directly in the context of the problem's logic of inheritance from a single - generation perspective here). Also, if we assume these are the children's genotypes, they are two different individuals, but the problem implies they are siblings from the same parents.
• Option 2 (\(Ff\) and \(Ff\)):

Using a Punnett square for \(Ff\times Ff\):

	\(F\)	\(f\)
\(f\)	\(Ff\)	\(ff\)

The offspring genotypes are \(FF:Ff:ff = 1:2:1\). So, it is possible to have a child with freckles (\(FF\) or \(Ff\)) and a child without freckles (\(ff\))

• Option 3 (\(FF\) and \(FF\)): All children would have the genotype \(FF\) (all have freckles)
• Option 4 (\(ff\) and \(ff\)): All children would have the genotype \(ff\) (all have no freckles)

Answer:

B. \(Ff\) and \(Ff\)