Problem Analysis:
We are tasked with determining the resulting percentages of blood types in the offspring when a male with type
AB blood is crossed with a female with type
O blood. This involves using a Punnett square to analyze the inheritance of ABO blood groups.
#### Key Points About ABO Blood Groups:
1.
Genotypes and Phenotypes:
-
Type A: Genotypes are `AA` or `AO`.
-
Type B: Genotypes are `BB` or `BO`.
-
Type AB: Genotype is `AB` (codominance).
-
Type O: Genotype is `OO`.
2.
Alleles:
- `A`: Dominant allele for Type A.
- `B`: Dominant allele for Type B.
- `O`: Recessive allele for Type O.
- Both `A` and `B` are codominant over each other, meaning if both are present, the phenotype is
AB.
3.
Parents' Genotypes:
- Male with
AB blood: Genotype is `AB`.
- Female with
O blood: Genotype is `OO`.
Step-by-Step Solution:
#### 1. Identify the Gametes:
-
Male (AB):
- Since the male has the genotype `AB`, his gametes will be:
- `A`
- `B`
-
Female (O):
- Since the female has the genotype `OO`, her gametes will be:
- `O`
- `O`
#### 2. Construct the Punnett Square:
We now combine the gametes from the male and female to determine the possible genotypes of the offspring.
| | O | O |
|-------|-------|-------|
|
A | AO | AO |
|
B | BO | BO |
#### 3. Determine the Phenotypes:
-
AO: This genotype results in
Type A blood.
-
BO: This genotype results in
Type B blood.
From the Punnett square, we see that all four boxes contain either `AO` or `BO`. Therefore, the possible phenotypes are:
-
Type A (from `AO`)
-
Type B (from `BO`)
#### 4. Calculate the Percentages:
- There are
4 total boxes in the Punnett square.
-
Type A (`AO`) appears in
2 boxes.
-
Type B (`BO`) appears in
2 boxes.
-
Type AB does not appear.
-
Type O does not appear.
Thus, the percentages are:
-
Type A: \( \frac{2}{4} \times 100\% = 50\% \)
-
Type B: \( \frac{2}{4} \times 100\% = 50\% \)
-
Type AB: \( 0\% \)
-
Type O: \( 0\% \)
Final Answer:
\[
\boxed{
\begin{aligned}
\text{Type A: } & 50\% \\
\text{Type B: } & 50\% \\
\text{Type AB: } & 0\% \\
\text{Type O: } & 0\%
\end{aligned}
}
\]
Parent Tip: Review the logic above to help your child master the concept of blood type punnett square worksheet.
