Question

There are normally four total α-globin alleles present on chromosome 16, two per chromosome. How many α-globin alleles are present on each chromosome?

1) One
2) Two
3) Three
4) Four

Answer 1

Each chromosome 16 has two α-globin alleles. Adults have hemoglobin A with 2α2β chains and fetal hemoglobin with 2α2y chains. α-thalassemia results from decreased α-chain synthesis but is mitigated by having two pairs of α-globin genes.

Step-by-step explanation:

There are normally four total α-globin alleles present on chromosome 16, implying that there are two α-globin alleles present on each chromosome. Thus, the correct answer to the question of how many α-globin alleles are present on each chromosome 16 is option 2) Two.

The α-globin genes are essential in the formation of various types of hemoglobin. In adults, hemoglobin A (HbA) has 2α2β chains, while fetal hemoglobin (HbF) has 2α2y chains, and minor adult hemoglobin (Hb A2) comprises 2α2δ chains.

α-thalassemia is a condition that results from the decreased synthesis of the α-chain of globin. This situation can lead to an imbalance in the globin chain production, causing various health issues. However, the presence of two pairs of α-globin genes usually provides a safeguard against the complete absence of α-chains.