Nucleotide sequences of the γ chain gene exon VIII. Single-stranded DNA, amplified by the asymmetrical PCR method,^7,8  from the γ chain gene exon VIII derived from a healthy subject or the patient, was subjected to direct nucleotide sequencing using ³⁵S-dATP and Sequenase. The pertinent portion of the autoradiography of urea-polyacrylamide gel electrophoresis is shown. Both G and A (arrow) were detected at position 5884 of the patient γ chain gene, coding for Ala (GCT) and Thr (ACT), whereas only G for Ala (GCT) was identified at the same position of the normal γ chain gene.