Abstract: A biotinylated target nucleic acid can be isolated from a mixture of nucleic acids using a capture reagent comprising avidin. The targeted nucleic acid is complexed with avidin on a substrate and separated from uncomplexed materials. The complex is heated at above about 65.degree. C. for a suitable time to cleave the avidin-biotin bonds to release the desired targeted nucleic acid. Upon release, the targeted nucleic acid can be collected or detected in a suitable manner, such as with a complementary probe. This method is also useful for preparing single-stranded DNA for a number of uses.