The invention relates to novel oligonucleotides comprising a signalling pair and at least two hydrophobic nucleotides. The oligonucleotide analogues are useful for detecting the status of nucleic acid sequences, such as presence, expression, methylation and/or mutation, in particular single point mutations and other sequences where the variation between the correct target and other targets may vary in as little as one nucleotide. The invention also relates to new ways of detecting sequence differences and optimizing conditions by using oligonucleotide analogues and readily available instruments. In particular the invention relates to specifically detecting quantity of a target nucleic acids or detecting one sequence over others that may vary in as little as one nucleotide using oligonucleotides or oligonucleotide analogues comprising a signalling pair and at least two hydrophobic nucleotides, such as a nucleotide analogue comprising an intercalator.