A man with normal red blood cells is married to a woman who is a sickle cell carrier. With the aid of a genetic diagram, explain the genetic constitution of their children

Here is the genetic diagram explaining the genetic constitution of their children:

Let 'A' represent the allele for normal hemoglobin and 'S' represent the allele for sickle cell hemoglobin.

• Man with normal red blood cells: His genotype is AA (homozygous dominant).
• Woman who is a sickle cell carrier: Her genotype is AS (heterozygous).

Parental Genotypes:
Man: AA
Woman: AS

Gametes:
Man: A, A
Woman: A, S

Punnett Square:

$$\begin{array}{|c|c|c|} \hline \text{Gametes} & \text{A} & \text{A} \\ \hline \text{A} & \text{AA} & \text{AA} \\ \hline \text{S} & \text{AS} & \text{AS} \\ \hline \end{array}$$

Genetic Constitution of Children:

• Genotypes:

  • 50% of the children will have the genotype AA.
  • 50% of the children will have the genotype AS.

• Phenotypes:

  • Children with genotype AA will have normal red blood cells (not affected by sickle cell disease and not carriers).
  • Children with genotype AS will be sickle cell carriers (they have normal red blood cells but carry the sickle cell trait and can pass it on to their children).

Therefore, there is a 50% chance for each child to have normal red blood cells and a 50% chance for each child to be a sickle cell carrier.