Patent ID: 7642057

Claim:
A method of determining the presence of a gene deletion in a sample of eukaryotic origin, using in situ hybridization, comprising the steps of: a) contacting said sample with a hybridization solution comprising at least two sets of hybridization probes, wherein at least one set comprises one or more peptide nucleic acid probes capable of hybridising to specific nucleic acid sequences in a chromosome, and at least one set comprises one or more probes capable of hybridising to specific nucleic acid sequences related to the gene deletion, wherein each probe is labelled directly or indirectly with at least one detectable label, wherein the detectable label of the at least one set of hybridization probes is different from the detectable label of the at least one other set of hybridization probes and optionally a hybrid destabilising agent in an amount effective to decrease the melting temperature of hybrids formed between said nucleic acid sequences and said peptide nucleic acid probes so as to increase the ratio between specific and non-specific binding, b) removing unbound and non-specifically bound probes, and c) determining the presence of the bound probes in the preparation.