A man is heterozygous for sickle cell anemia and homozygous dominant for familial hypercholesterolemia. Knowing that these genes are located on different chromosomes and using the information below, predict his possible sperm.

Question

Sickle Cell Anemia
A=Normal hemoglobin
a=Abnormal hemoglobin (Sickle Cell)

B=Familial Hypercholesterolemia (abnormal LDL protein receptor)
b=Normal LDL protein receptor)
Responses
A abab
B AB and abAB and ab
C AB and aBAB and aB
D AA and BB

Answer 1

To determine the possible sperm types produced by the man who is heterozygous for sickle cell anemia (Aa) and homozygous dominant for familial hypercholesterolemia (BB), we need to consider the combinations of alleles he can pass on.

1. The man is heterozygous for sickle cell anemia:

   • His genotype is Aa, meaning he can pass either A (normal hemoglobin) or a (abnormal hemoglobin) to his offspring.

2. He is homozygous dominant for familial hypercholesterolemia:

   • His genotype is BB, meaning he can only pass on B (abnormal LDL protein receptor) to his offspring.

Now, let's combine these two:

• From the sickle cell allele (Aa), he can contribute either A or a.
• From the familial hypercholesterolemia allele (BB), he can only contribute B.

The possible combinations for sperm production would therefore be:

• AB (if he contributes A from sickle cell)
• ab (if he contributes a from sickle cell, but he will still have B from BB because he can only contribute B)

Thus, the possible sperm combinations are:

1. AB
2. aB

So the correct response from the options provided is C: AB and aB.