One would expect that defects in the globin genes would be so serious as to cause death in utero. Which of the following explains how some thalassemias are found in living people? A)in $\beta$-thalassemia, the use of the $\gamma$ subunit allows individuals to live a normal lifespan B)individuals who completely lack functional $\alpha$ subunits can live if placed in a hypobaric chamber to induce hypoxia C)since humans have 4 copies of the $\alpha$ chain gene, effects are only seen when at least 3 of the genes are nonfunctional D)individuals with nonfunctional $\alpha$ chain genes can make $\beta$₂$\gamma$₂ tetramers that function normally E)none of the above

Question

Quizplus · Accepted Answer

Thalassemias are caused by mutations in the globin genes, which result in reduced or absent synthesis of the respective globin chains. However, humans have two copies of the α-globin gene and two copies of the β-globin gene. Therefore, effects are only seen when at least three of the four genes are nonfunctional. This is why certain thalassemias, such as α-thalassemia minor, can be found in living people.

One Would Expect That Defects in the Globin Genes Would β\betaβ

One Would Expect That Defects in the Globin Genes Would $\beta$