Abstract: The invention discloses methods of reducing background signal in nucleic acid amplification reactions by the use of primers in the case of isothermal amplification which include at least one modification selected from a nucleotide analogue, a hairpin loop at the 5′ end of the primer, a ribonucleotide or a fluor or quencher. For more general nucleic acid amplification reactions the primer includes at least two of the modifications.

Abstract: A method of analysing a nucleic acid is disclosed which involves the use of a mixture of labelled oligonucleotides in solution and an array of immobilized oligonucleotides. The target nucleic acid is incubated with the mixture of labelled oligonucleotides. Those labelled oligonucleotides which hybridize are recovered and incubated with the array of immobilized oligonucleotides. Sequence information is obtained by observing the location of the label on the array. The method is particularly suitable for determining differences between nucleic acids.

Abstract: A method of sequencing a target nucleic acid using primer extension mass spectroscopy to generate an observed mass spectrum, on which base calling cycles are carried out using calibrated inter-peak mass difference values such that: each called base allows mass calculation for the base-called peak in the observed mass spectrum; this calculated mass is then used as a further calibration point for subsequent rounds of base calling. A reaction mixture of all four base-specific chain extension nucleotides and four chain termination nucleotide analogues. A method of performing mass spectroscopy, which method comprises subjecting molecular ions which have been chemically charged in a predetermined manner to time-of-flight or Fourier transform mass spectroscopy.