Question

1. Determining Inheritance using Punnett Squares

The condition of sickle cell anemia is recessive and only the homozygous recessive individuals are adversely affected. Interestingly, heterozygous individuals have increased resistance to Malaria which is caused by a Plasmodium parasite that infects red blood cells. A heterozygous individual has red blood cells that are minimally affected but are altered enough so that Plasmodium cannot infect the cells. This is one reason why this allele persists in the population – in the heterozygous state it gives the individual an advantage for survival in some environments.

Veronica, who has the sickle cell condition, and Mason who does not have the condition have a child. They are worried about the having a child with sickle cell anemia and malaria because they are moving to a part of Africa where the Plasmodium is common. Who in this family should be worried about sickle cell anemia and contracting malaria?

Answer 1

Answer-

According to the given question-

We know that sickle cell anemia, a disorder where the red blood cells or r.b.c. become sickle-shaped is a recessive disorder, and individuals who are homozygous recessive will get adversely affected with sickle cell anemia. but individuals who are heterozygous are work as a carrier for sickle cell anemia, but they are normal and are resistance to Malaria, a disease caused by a parasite called Plasmodium generally affects the r.b.c. So the individuals which are heterozygous, they are less chance of getting infected with Plasmodium and their allele is generally persisting in the population.

Here we have a female named- Veronica, has sickle cell condition, which means that Veronica is homozygous recessive married with a male named- Mason does not have sickle cell condition, which means that Mason is either homozygous dominant or heterozygous, and they have a child.

so the chance of the child having sickle cell condition may be-

Suppose Mason is heterozygous then -

The genotype of Veronica = ss

The genotype of Mason = Ss

a cross between Ss ss

	s	s
S	Ss (Normal)	Ss (Normal)
s	ss (Sickle cell condition)	ss (Sickle cell condition)

This means that out of total offspring produced half offspring will be normal, resistent to maleria and half offspring will be infected with sickle cell condition and are very succeptible for maleria. so there are 50 % of chances that their child will be normal and 50 % chances that the child will be infected with sickle cell condition when Mason is heterozygous.

When Mason is homozygous dominant -

a cross between SS ss

	s	s
S	Ss (Normal)	Ss (Normal)
S	Ss (Normal)	Ss (Normal)

All child will be Normal and are resistent to maleria, because they all are heterozygous.

• Veronica who have sickle cell condition, have higher chances of gettiing infected with Plasmodium and have high chances of contracting malaria when they move to a part of africa but when Mason is heterozygous then there are 50 % chance that the child have sickle cell condition and infected with Plasmodium and have high chances of contracting malaria.