Representative 1.5% agarose gel electrophoresis of the amplified PCR products for characterizing α-globin gene deletion types by multiplex gap PCR. The 2 kb, 1.8 kb, 1.6 kb, 1.4 kb and 1.2 kb represent 3.7 kb deletion fragment (-α
3.7), normal fragment (αα), 4.2 kb deletion fragment (-α
4.2), SEA type deletion fragment (–SEA), and THAI type deletion fragment (–THAI), respectively. The M represents the 1 kb DNA ladder. Lanes 1–4 (positive controls) are genotypes as follows: -α
3.7/α
α, -α
4.2/α
α, –SEA/αα, and –THAI/αα, respectively. Lanes 5, 6, 8, 9, and 11–13 are normal α-globin genotype (αα/αα). Lanes 7, 10, and 15 are heterozygous α-thalassemia 1 (–SEA/α
α). Lane 14 is homozygous α-thalassemia 2 (-α
3.7/-α
3.7).