Question

Sarah has type A blood, and Jesse has type O blood. Their son has type B blood. Can Jesse be the baby daddy? He is a bit worried. Please complete the Punnett squares to determine the possibilities. a No, type B blood must be homozygous b No, this is impossible c Yes, if one parent is heterozygous d Yes, if both parents are heterozygous

Answer 1

To determine whether Jesse could be the biological father of a child with type B blood, we should evaluate the potential genotypes of the parents involved.

**Blood Type Basics:**
- Type A blood can result from genotypes **AA** (homozygous) or **AO** (heterozygous).
- Type O blood is represented by the genotype **OO** (homozygous).
- Type B blood can result from genotypes **BB** (homozygous) or **BO** (heterozygous).

**Given:**
- Sarah has type A blood (genotype unknown: could be AA or AO).
- Jesse has type O blood (genotype OO).
- Their son has type B blood (genotype BO or BB).

### Step 1: Construct Punnett Squares

#### Case 1: Sarah is homozygous (AA)

| | A | A |
|----------|---------|---------|
| O | AO | AO |
| O | AO | AO |

- Offspring genotypes: 100% AO (Type A).
- **Conclusion:** If Sarah is AA, then type B (BO or BB) cannot occur.

#### Case 2: Sarah is heterozygous (AO)

| | A | O |
|----------|---------|---------|
| O | AO | OO |
| O | AO | OO |

- Offspring genotypes: 50% AO (Type A), 50% OO (Type O).
- There is also a 0% chance for BO (Type B) and 0% for BB (Type B).
- **Conclusion:** If Sarah is AO, then type B (BO or BB) cannot occur.

### Conclusion
In both scenarios, it is impossible for Sarah (either AA or AO) and Jesse (OO) to produce a child with type B blood. Therefore, Jesse cannot be the biological father of the child with type B blood.

**The best answer from the options provided:**
b No, this is impossible.