Question

free earlobes are dominant over attached earlobes. what is the probability that a woman with attached earlobes (homozygous recessive) will have children with attached earlobes if their father has free earlobes (heterozygous)?
1 in 10
3 in 4
1 in 2
all of the children will have attached earlobes.

Explanation:

Step1: Determine genotypes

Let \(A\) represent the allele for free earlobes (dominant) and \(a\) represent the allele for attached earlobes (recessive). The woman has attached earlobes, so her genotype is \(aa\). The father has free earlobes and is heterozygous, so his genotype is \(Aa\).

Step2: Set up Punnett square

The possible gametes from the woman (\(aa\)) are all \(a\). The possible gametes from the father (\(Aa\)) are \(A\) and \(a\). The Punnett square is:

	\(A\)	\(a\)

Step3: Calculate probability

There are 2 possible genotypes (\(Aa\) and \(aa\)) for the offspring. The probability of having attached earlobes (\(aa\)) is \(\frac{1}{2}\)

Answer:

1 in 2