The inventors have isolated cloned cDNA encoding the RNA genome of Human Immunodeficiency Virus type 1 (HIV-1). Various clones are described, which encode different regions of the genome, including those regions encoding viral antigens or proteins. Hybridization results indicate the difference between the HIV-1 clones and those of HTLV-I and HTLV-II. The inventors have also produced a restriction map of the entire cloned genomic sequence in order to facilitate further subcloning and using the restriction fragments in other hybridization tests and in methods to express encoded sequences.