hybridization complex formation method which stability is substantially independent of the base composition of the two molecules of hybridized nucleic acids

The invention discloses a method for producing a hybridisation complex whose stability is substantially independent of the base composition of two hybridised nucleic acid molecules, consisting in contacting a first nucleic acid molecule with a second nucleic acid molecule under conditions enabling the formation of a specific hybridisation complex. The invention is characterised in that at least one of the four types of bases contained in the sequence of the first and/or of the second nucleic acid molecule is a modified base having pairing properties close to those of the natural base it replaces, such that at least one of the two types of the base pair contained in the composition of the complex comprises a modified base and in that the totality of the base pairs contained in the composition of the said complex has a like stability.