α Globin gene analysis in families H and G. (A) Composite autoradiograph of a Southern blot after digestion with the restriction enzyme BamHI and hybridization with an α probe (1.5-kilobase [kb] PstI fragment). The first 5 lanes are controls (lanes 1-3 show the-α^3.7/αα; lane 4, the-α^3.7/-α^3.7; and lane 5, the αα/αα gene arrangements). Lane 6 shows the homozygote for the quadruple α-gene arrangement and lane 7 shows his father (family H). Lanes 8 and 9 are duplicate samples from the homozygote for the triple α gene arrangement, collected on more than one occasion, and lanes 10 and 11 are from his parents (family G). (B). Schematic, outlining the α globin gene rearrangement from an unequal crossover resulting in deletion or insertion of 3.7 kb DNA.