Applications with and Methods for Producing Selected Interstrand Cross-Links in Nucleic Acids

A method for preventing hybridization of a first chromosomal nucleic acid sequence, while permitting hybridization of a second chromosomal nucleic acid sequence, the method comprising:

• (a) providing a nucleic acid sequence that is complementary to a first chromosomal nucleic acid sequence wherein the complementary sequence or the first chromosomal nucleic acid sequence or both comprise a cross-linking agent, the cross-linking agent being capable of cross-linking the complementary sequence to the first chromosomal nucleic acid sequence;
• and
• (b) hybridizing the first chromosomal nucleic acid sequence to its complementary sequence in the presence of the second chromosomal nucleic acid sequence;
• thereby cross-linking the complementary sequence to the first chromosomal nucleic acid sequence;
• whereby the cross-linked first chromosomal nucleic acid sequence is prevented from further hybridizing and the second chromosomal nucleic acid sequences is permitted to hybridize.