Sickle cell disease is(1 point)

Here are the answers to the questions based on the genetics of sickle cell disease:

Question 1: Sickle cell disease is:

• [Choice B] a recessive inherited disorder

Sickle cell disease is caused by a mutation in the HBB gene on chromosome 11 and is inherited in an autosomal recessive manner. This means that an individual must inherit two copies of the sickle cell allele (one from each parent) to exhibit the disease.

Question 2: The reason that sickle cell is so common to people with ancestry from certain regions of the world is because:

• [Choice C] having sickle cell disease protects you from dying of malaria

Sickle cell trait (carrying one sickle cell allele and one normal allele) provides a selective advantage in regions where malaria is prevalent, as it offers some protection against severe forms of malaria. This increased survival may lead to a higher frequency of the sickle cell allele in these populations.

Question 3: True or false: Father is a carrier for sickle cell trait and mother has two normal alleles. There is a 50% chance that their child can have sickle cell disease (homozygous SS).

• Response: False

To analyze the scenario:

• The father is a carrier for sickle cell trait (genotype AS).
• The mother has two normal alleles (genotype AA).

The Punnett square for this scenario would look like this:

    A    A
  -----------
A |  AA |  AA |
  -----------
S |  AS |  AS |
  -----------

From this Punnett square, the possible genotypes of their offspring are:

• 50% AA (normal)
• 50% AS (carrier)

There are no offspring with the homozygous SS genotype, thus the statement is false.

If you have any further questions or clarifications needed, feel free to ask!