Abstract: The invention concerns the use of duplex oligonucleotides having both 2'-deoxyribonucleotides and ribonucleotides, wherein there is base pairing between the two types of nucleotides. The sequence of the oligonucleotide is selected so that the 3' and 5' most regions of the oligonucleotide are homologous with (identical to) the sequence of a preselected target gene of a cell. The two regions of homology embrace a region that is heterologous with the target sequence. The introduction of the oligonucleotide into the nucleus of the cell causes the alteration of the target gene such that the sequence of the altered target gene is the sequence of the heterologous region. Consequently, the oligonucleotides of the invention are termed Chimeric Repair Vectors (CRV). In one embodiment of the invention the target gene is a globin gene and the target cell is a hematopoietic stem cell. This embodiment can be used to correct certain hemoglobinopathies such as Sickle Cell Disease, .beta.

Abstract: The present invention concerns a polynucleotide having both ribonucleotides and deoxyribonucleotides in a first strand and solely deoxyribonucleotides in a second strand; wherein the strands are Watson-Crick paired and are linked by an oligonucleotide so that the polynucleotide has at most a single 3' and a single 5' end. These ends can be ligated so that the polynucleotide is a single continuous circular polymer. The polynucleotide can be used to induce specific alterations in targeted genes.