Question

the abo blood group has three different alleles: $i^{a}$, $i^{b}$, and $i$. the genotypes and phenotypes (blood types) for different combinations of the three alleles are shown in the table.
possible genotype
and phenotypes of
abo blood group
what percentage of offspring from a cross between a homozygous type a parent with a heterozygous type a parent is expected to contain the $i$ allele?
25%
75%
50%
100%

Explanation:

Step1: Determine the genotypes of the parents

A homozygous Type A parent has the genotype \(I^{A}I^{A}\). A heterozygous Type A parent has the genotype \(I^{A}i\).

Step2: Set up the Punnett square

The possible gametes from the \(I^{A}I^{A}\) parent are all \(I^{A}\). The possible gametes from the \(I^{A}i\) parent are \(I^{A}\) and \(i\).

	\(I^{A}\)	\(i\)

Step3: Calculate the proportion of offspring with the \(i\) allele

Out of the 2 possible genotypes (\(I^{A}I^{A}\) and \(I^{A}i\)), 1 has the \(i\) allele. So the proportion is \(\frac{1}{2}=0.5 = 50\%\)

Answer:

50%