Question

if a mom with ear lobes that were unattached at the bottom (ee) had a child with the father who had attached ear lobes (ee), what is the chance that the kid would have attached ear lobes? hint: (do the punnett square first and then count how many end up being ee)

Explanation:

Step1: Determine the genotypes

Let's assume the allele for unattached earlobes (E) is dominant and the allele for attached earlobes (e) is recessive. The mother has unattached earlobes but since the father has attached earlobes (ee), and if we assume the mother is heterozygous (Ee) (because if she was homozygous dominant (EE) all children would have unattached earlobes).

Step2: Create the Punnett square

The mother's gametes: E and e. The father's gametes: e and e.

	E	e
e	Ee	ee

Step3: Calculate the probability

Out of 4 possible offspring genotypes (Ee, ee, Ee, ee), 2 have the genotype (ee) for attached earlobes. The probability is $\frac{2}{4}=\frac{1}{2}$ or 50%.

Answer:

The chance that the kid would have attached ear lobes is $\frac{1}{2}$ or 50%.