How are globin chain genes organized?

The organization of globin chain genes is a well-defined aspect of human genetics, essential for understanding hemoglobin structure and function. There are two main clusters of globin genes located on separate chromosomes: the α-globin gene cluster is found on chromosome 16, while the β-globin gene cluster is located on chromosome 11.

The α-globin gene cluster contains two functional α genes (α1 and α2), along with pseudo genes, leading to the conclusion that the configuration involves two α genes. The β-globin gene cluster comprises a primary functional gene responsible for encoding the β globin chain, which is expressed in various forms, including fetal (δ) and adult (β) hemoglobin variants. Therefore, the statement regarding the arrangement having two α genes and one β gene correctly represents the current understanding of globin gene organization.

In essence, this structural organization enables the proper formation of hemoglobin, facilitating efficient oxygen transport by allowing the expression of different globin chains throughout development. Understanding this arrangement is key for comprehending related genetic disorders, such as thalassemia and sickle cell disease, which arise from mutations within these genes.