Structure of cloned δ-globin genes from a normal subject and a patient with δ-thabssemia; sequence polymorphisms found in the δ-globin gene region of Japanese individuals

Abstract

The δ-globin genes of a normal Japanese and a Japanese patient with homo-zygous δ-thalassemia were cloned, and the nucleotide sequence of a region including the gene was determined. Comparison of the nucleotide sequences of these two individuals with that of pHδl, δ-globin clone from the gene library constructed by Maniatis etal. , showed differences in the large intervening sequence (IVS 2), at positions 137, 151, 186, 188, 291, 292 and 540 as one base substitutions, at 339 and 823 as one base additions, at 548 as a one base deletion, and a 9 bp duplication between positions 651 and 659, and differences in the 3′-flanking sequence at 51 and 98 nucleotides 3′ to the AATAAA sequence. However, in the region studied, no differences was observed in the nucleotide sequences of the normal subject and the patient with δ-thalassemia. Therefore, these differences may represent polymorphisms of the δ-globin gene present in Japanese individuals. These data suggest that IVS 2 is more divergent than other regions, and that a DNA region(s) other than the globin gene may affect expression of the gene.