Evidence of differential selection for the −α3.7 and −α4.2 single‐α‐globin gene deletions within the same population

• DOI: 10.1111/ejh.12058
• Publication Date: 2013-01-04T16:28:33Z
• Authors: Zhi Min Yap; Kar Mun Sun; Clara R.L. Teo; Arnold S.C. Tan; Samuel S. Chong
• Keywords: Gene conversion

Since the 1950s, a strong correlation between high carrier rates for β-thalassemia mutations and selective survival advantage in tropical subtropical 'malarial belt' regions has been established. Due to relatively more complex genetics of α-thalassemia, similar relationship was demonstrated α-globin gene only from 1980s, with both single- double-α-globin deletions prevalent malarial belt. Mechanistically, single-α-globin arise non-allelic recombination homologous α1 (HBA1) α2 (HBA2) globin genes. Compared -α(3.7) ααα(anti3.7) rightward crossover alleles, much less is known about -α(4.2) ααα(anti4.2) leftward alleles. We performed survey 1,285 unselected cord blood samples 3 major ethnic groups Singapore. Overall, frequency deletion significantly higher than its reciprocal triplication, consistent positive selection single-gene deletion. In marked contrast, there no significant difference suggesting absence The allele frequencies also suggested that at X Z homology boxes are similar. Taken together, these observations suggest differential alleles within same population. Further population biological studies may be required explain current observations.