Evidence of Selection for the α-Globin Gene Deletions and Triplications in a Southern Chinese Population

Abstract

α⁺-Thalassemia (α⁺-thal) is common in Southern China. The high frequency could be due to over dominant selection through malaria. Two molecular mechanisms that produce α⁺-thal have been defined; one results in the –α^3.7 (rightward) deletion and reciprocal ααα^{anti 3.7} triplication, and the other one results in the –α^4.2 (leftward) deletion and reciprocal ααα^{anti 4.2} triplication. Considering that each de novo event produced a chromosome with an α gene deletion and a chromosome with an α triplication, if there is no favorable allele, one would expected to find the same allelic frequencies. We found a favorable selection for the –α^3.7 deletion in the Chinese population, and we also found that the α triplication is not as rare as was first thought, especially for the ααα^{anti 3.7} triplication.

• α-Thalassemia (α-thal)
• positive selection
• single-gene deletions
• triplications

Declaration of interest

This study was supported by Bureau of Science and Technology of Guangzhou Municipality (201300000086), People’s Republic of China. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.