Question
The Punnett square below shows the possible genotypes for the offspring of two parents that each have one copy of the mutated hemaglobin-Beta gene. Neither parent has sickle cell disease. In the Punnett square, the “A” represents the normal form of the gene and the “a” represents the form of the gene with the mutation.

Which analysis best describes the probability of an offspring having or not having sickle cell disease, and carrying or not carrying the defective gene for sickle cell disease?
A.
There is a 25% probability that an offspring will have sickle cell disease.
B.
There is a 75% probability that an offspring will not have sickle cell disease and will not carry the defective gene.
C.
There is a 25% probability that an offspring will not have sickle cell disease, but will carry the defective gene.
D.
There is a 50% probability that an offspring will have sickle cell disease.
Multiple Choice Question
Part B:
Based on the information in the text and Part A above, which statement best describes how sickle cell disease is inherited?
A.
Sickle cell disease is inherited as a dominant trait; an individual with a single copy of the defective gene will have the disease.
B.
Sickle cell disease is inherited as a dominant trait in males, but as a recessive trait in females.
C.
Sickle cell disease is carried by females, but only males can inherit the disease.
D.
Sickle cell disease is inherited as a recessive trait; an individual must have two copies of the defective gene in order to have the disease.

Which analysis best describes the probability of an offspring having or not having sickle cell disease, and carrying or not carrying the defective gene for sickle cell disease?
A.
There is a 25% probability that an offspring will have sickle cell disease.
B.
There is a 75% probability that an offspring will not have sickle cell disease and will not carry the defective gene.
C.
There is a 25% probability that an offspring will not have sickle cell disease, but will carry the defective gene.
D.
There is a 50% probability that an offspring will have sickle cell disease.
Multiple Choice Question
Part B:
Based on the information in the text and Part A above, which statement best describes how sickle cell disease is inherited?
A.
Sickle cell disease is inherited as a dominant trait; an individual with a single copy of the defective gene will have the disease.
B.
Sickle cell disease is inherited as a dominant trait in males, but as a recessive trait in females.
C.
Sickle cell disease is carried by females, but only males can inherit the disease.
D.
Sickle cell disease is inherited as a recessive trait; an individual must have two copies of the defective gene in order to have the disease.
Answers
GPT-4o mini
To analyze the probability of offspring having or not having sickle cell disease and carrying or not carrying the defective gene, we can use the information typically presented in a Punnett square, knowing the following:
- "A" represents the normal allele.
- "a" represents the mutated allele that leads to sickle cell disease.
From two parents each carrying one copy of the mutated gene ("Aa"), we can establish the following combinations for their offspring:
1. AA - Normal (not a carrier)
2. Aa - Normal (carrier)
3. aA - Normal (carrier)
4. aa - Sickle cell disease
The Punnett square would look like this:
```
A | a
----------------
A | AA | Aa
----------------
a | Aa | aa
```
Based on this Punnett square, we can derive the following probabilities:
- **AA (Normal, not a carrier):** 25%
- **Aa (Carrier, normal):** 50% (25% + 25%)
- **aa (Sickle cell disease):** 25%
Now, we can evaluate the statements provided:
**Part A:**
A. There is a 25% probability that an offspring will have sickle cell disease. **(True)**
B. There is a 75% probability that an offspring will not have sickle cell disease and will not carry the defective gene. **(False; there is only a 25% probability of being AA)**
C. There is a 25% probability that an offspring will not have sickle cell disease, but will carry the defective gene. **(True; Aa is indeed a carrier and makes up 50% of the outcomes, but there's no direct 25% mention for only carriers)**
D. There is a 50% probability that an offspring will have sickle cell disease. **(False; it's 25%)**
The best choice here is:
**A. There is a 25% probability that an offspring will have sickle cell disease.**
---
**Part B:**
For the inheritance pattern of sickle cell disease:
A. Sickle cell disease is inherited as a dominant trait; an individual with a single copy of the defective gene will have the disease. **(False; it's recessive)**
B. Sickle cell disease is inherited as a dominant trait in males, but as a recessive trait in females. **(False; it's not sex-specific in inheritance)**
C. Sickle cell disease is carried by females, but only males can inherit the disease. **(False; both genders can carry and inherit)**
D. Sickle cell disease is inherited as a recessive trait; an individual must have two copies of the defective gene in order to have the disease. **(True)**
The best choice is:
**D. Sickle cell disease is inherited as a recessive trait; an individual must have two copies of the defective gene in order to have the disease.**
- "A" represents the normal allele.
- "a" represents the mutated allele that leads to sickle cell disease.
From two parents each carrying one copy of the mutated gene ("Aa"), we can establish the following combinations for their offspring:
1. AA - Normal (not a carrier)
2. Aa - Normal (carrier)
3. aA - Normal (carrier)
4. aa - Sickle cell disease
The Punnett square would look like this:
```
A | a
----------------
A | AA | Aa
----------------
a | Aa | aa
```
Based on this Punnett square, we can derive the following probabilities:
- **AA (Normal, not a carrier):** 25%
- **Aa (Carrier, normal):** 50% (25% + 25%)
- **aa (Sickle cell disease):** 25%
Now, we can evaluate the statements provided:
**Part A:**
A. There is a 25% probability that an offspring will have sickle cell disease. **(True)**
B. There is a 75% probability that an offspring will not have sickle cell disease and will not carry the defective gene. **(False; there is only a 25% probability of being AA)**
C. There is a 25% probability that an offspring will not have sickle cell disease, but will carry the defective gene. **(True; Aa is indeed a carrier and makes up 50% of the outcomes, but there's no direct 25% mention for only carriers)**
D. There is a 50% probability that an offspring will have sickle cell disease. **(False; it's 25%)**
The best choice here is:
**A. There is a 25% probability that an offspring will have sickle cell disease.**
---
**Part B:**
For the inheritance pattern of sickle cell disease:
A. Sickle cell disease is inherited as a dominant trait; an individual with a single copy of the defective gene will have the disease. **(False; it's recessive)**
B. Sickle cell disease is inherited as a dominant trait in males, but as a recessive trait in females. **(False; it's not sex-specific in inheritance)**
C. Sickle cell disease is carried by females, but only males can inherit the disease. **(False; both genders can carry and inherit)**
D. Sickle cell disease is inherited as a recessive trait; an individual must have two copies of the defective gene in order to have the disease. **(True)**
The best choice is:
**D. Sickle cell disease is inherited as a recessive trait; an individual must have two copies of the defective gene in order to have the disease.**