Abstract: The invention is a method for detecting whether an organism is homozygous or heterozygous in a target nucleotide. The method combines hybridization of two differently labelled probes A and B on either side of a restriction site, restriction endonuclease digestion, and detection of the labels in the resulting digest. If an organism is: homozygous then the labels will be present in the ratio 1:1 or 1:0; or if heterozygous then the labels will be present in the ratio 1:2. Either immobilized array technology or electrophoretic separation may be used.

Abstract: A method for genotyping a subject with respect to a gene or target nucleic acid sequence associated with a pathological condition, said method comprising contacting an allele specific oligonucleotide immobilized to a solid support with a single-stranded from of RNA or DNA from a subject to be tested labeled directly or indirectly with a reporter molecule capable of giving an identifiable signal under conditions which permit hybridization of single stranded RNA or DNA which is exactly complementary to the immobilized allele specific oligonucleotide but substantially less or no hybridization of non-complementary single-stranded RNA or DNA molecules and then screening for the presence or absence or level of reporter molecule which provides an indicator of the genetic identity of the single-stranded RNA or DNA molecule which in turn provides the genotype of the subject.

Abstract: The invention is a method for detecting whether an organism is homozygous or heterozygous in a target nucleotide. The method combines hybridization of two differently labelled probes A and B on either side of a restriction site, restriction endonuclease digestion, and detection of the labels in the resulting digest. If an organism is: homozygous then the labels will be present in the ratio 1:1 or 1:0; or if heterozygous then the labels will be present in the ratio 1:2. Either immobilized array technology or electrophoretic separation may be used.