In vitro capture of nucleic acids via modified oligonucleotides and magnetic beads

A method is disclosed for capturing one or more target sequences utilizing modified, high stringency nucleic acids and strand displacement stategies. In this method, one or more modified, high stringency oligonucleotide (MHSO) conjugates are selected in which the conjugates are constructed from at least one modified nucleic acid, such as, for example, a locked nucleic acid ("LNA") and a linking molecule. When incubated with a sample of nucleic acids, these MHSO conjugates capture the target sequence by selectively binding to complementary sequences of DNA or RNA, which may be either single or double stranded. Once bound, the resulting complexes constitute hybridized duplexes containing both a targeted sequence portion and a MHSO conjugate portion. The captured target sequences are separated from the sample by using a linking source that binds to the linking molecule of the hybridized duplex and extracting the linking source with the bound duplex from the sample.