Full-length, single-stranded rabbit globin cDNA, synthesized by AMV reverse transcriptase, apparently contains a small double-stranded sequence (hairpin) at the 3’terminus. This cDNA can serve as template-primer for E. coli DNA polymerase I, which synthesizes a strand complementary to the cDNA and covalently bound to it. The loop connecting the two strands can be cut by Sl nuclease. Reassociation, hybridization, and restriction endonuclease studies, as well as electrophoretic analyses, indicate that the sequential actions of reverse transcriptase, DNA polymerase I, and Sl nuclease generate full-length, doublestranded synthetic globin genes.