Question
Sickle cell anemia is known to run in a family. A pedigree chart for this family is shown below.
The parents are shown at the top and from left to right appear as a half-shaded circle next to a half shaded square.The two are connected by a straight line. Below the parent pair is a vertical straight line connecting the next row of circles and squares which are the offspring. Starting from the left an unshaded square, half-shaded circle, another half-shaded circle and a completely shaded square are shown. All these are also connected by a horizontal straight line.
What percentage of the offspring have sickle cell anemia?
Group of answer choices
25%
100%
0%
50%
The parents are shown at the top and from left to right appear as a half-shaded circle next to a half shaded square.The two are connected by a straight line. Below the parent pair is a vertical straight line connecting the next row of circles and squares which are the offspring. Starting from the left an unshaded square, half-shaded circle, another half-shaded circle and a completely shaded square are shown. All these are also connected by a horizontal straight line.
What percentage of the offspring have sickle cell anemia?
Group of answer choices
25%
100%
0%
50%
Answers
GPT-4o mini
To determine the percentage of offspring with sickle cell anemia based on the provided pedigree chart information, we need to analyze the phenotypes of the individuals involved.
1. The "half-shaded" symbols indicate carriers of the sickle cell trait (they have one normal allele and one sickle cell allele).
2. The "unshaded" square represents an individual with no sickle cell traits (has two normal alleles).
3. The "completely shaded" square indicates an individual with sickle cell anemia (has two sickle cell alleles).
Given this information:
- The parents are half-shaded (carriers) and half-shaded (carrier).
- The offspring include an unshaded square (normal), two half-shaded circles (carriers), and one completely shaded square (has sickle cell anemia).
From the offspring:
- 1 offspring is completely shaded, which means he/she has sickle cell anemia.
- 2 offspring are half-shaded, meaning they are carriers.
- 1 offspring is unshaded, meaning he/she does not have the disease.
Now let's tally the offspring:
- Total offspring = 4
- Offspring with sickle cell anemia = 1
To calculate the percentage of the offspring that have sickle cell anemia:
\[
\text{Percentage with sickle cell anemia} = \left( \frac{\text{Number with sickle cell anemia}}{\text{Total number of offspring}} \right) \times 100
\]
\[
\text{Percentage with sickle cell anemia} = \left( \frac{1}{4} \right) \times 100 = 25\%
\]
Therefore, the answer is **25%**.
1. The "half-shaded" symbols indicate carriers of the sickle cell trait (they have one normal allele and one sickle cell allele).
2. The "unshaded" square represents an individual with no sickle cell traits (has two normal alleles).
3. The "completely shaded" square indicates an individual with sickle cell anemia (has two sickle cell alleles).
Given this information:
- The parents are half-shaded (carriers) and half-shaded (carrier).
- The offspring include an unshaded square (normal), two half-shaded circles (carriers), and one completely shaded square (has sickle cell anemia).
From the offspring:
- 1 offspring is completely shaded, which means he/she has sickle cell anemia.
- 2 offspring are half-shaded, meaning they are carriers.
- 1 offspring is unshaded, meaning he/she does not have the disease.
Now let's tally the offspring:
- Total offspring = 4
- Offspring with sickle cell anemia = 1
To calculate the percentage of the offspring that have sickle cell anemia:
\[
\text{Percentage with sickle cell anemia} = \left( \frac{\text{Number with sickle cell anemia}}{\text{Total number of offspring}} \right) \times 100
\]
\[
\text{Percentage with sickle cell anemia} = \left( \frac{1}{4} \right) \times 100 = 25\%
\]
Therefore, the answer is **25%**.