Abstract: Methods and compositions for efficient targeting and modification of target sequences in duplex DNA are provided, utilizing oligonucleotides or oligonucleotide compositions containing two domains. The first domain comprises an entity capable of recognizing a double-stranded DNA sequence. This can be a protein, peptide, antibiotic, minor groove binding agent or a nucleotide sequence capable of triplex formation The second domain, which is covalently joined to the first, is capable of recognizing a single-stranded DNA sequence. This second domain will most often be complementary, in the Watson-Crick sense, to a target sequence in the double-stranded nucleic acid. The second domain can optionally carry one or more modifying groups, capable of causing a mutation, a pre-mutagenic lesion, or some other type of heritable change in the target sequence.

Abstract: Novel methods and reagents for determining the presence of specific nucleic acid base sequences by employing crosslinking reactions of unique molecules capable of forming covalent bonds which are bonded with various labels or ligands for amplication.Single stranded nucleic acid probes are employed which contain complementary base sequences to nucleic acid target molecules. By first hybridizing and then forming covalent bonds between the probe and target the amount of label in the crosslinked hybrid can be measured as an extremely sensitive method for assaying for specific nucleic acid sequences.