Question

sickle cell anemia is a genetic disease caused by a recessive allele. sickle cell anemia affects the hemoglobin in red blood cells, making them the shape of crescents instead of disks. the disease can cause pain and damage blood vessels. a genetic counselor meets with a man and a woman that both are carriers of sickle cell anemia. carriers have one copy of the sickle cell allele and one copy of the allele for making normal hemoglobin. what is the probability that the couple would have a child that was also a carrier for sickle cell anemia? 0% 25% 50% 75% 100%

Explanation:

Step1: Define parental genotypes

Let the normal allele be $A$ and the sickle cell allele be $a$. Both parents are carriers, so their genotypes are $Aa$.

Step2: Set up Punnett square

$$\begin{array}{c|cc} & A & a \\ \hline A & AA & Aa \\ a & Aa & aa \\ \end{array}$$

Step3: Identify carrier offspring

Carrier genotypes are $Aa$. There are 2 out of 4 total genotypes.

Step4: Calculate probability

The probability is $\frac{2}{4} = 50\%$.

Answer:

50%