Oligonucleotides useful for detecting and analyzing nucleic acids of interest
The invention features improved nucleic acids and methods for expression profiling of mRNAs, identifying and profiling of particular mRNA splice variants, and detecting mutations, deletions, or duplications of particular exons or other splice variants, e.g., alterations associated with a disease such as cancer, in a nucleic acid sample, e.g., a biological sample or a patient sample.
1. A method of detecting a cDNA, said method comprising conducting PCR on said cDNA using an oligomer to hybridize to said cDNA, wherein said oligomer has a total of 8 or 9 nucleotides and at least 50% of said nucleotides are LNA nucleotide analogues, wherein said oligomer comprises at least one non-modified deoxyribonucleotide, and wherein said oligomer comprises a fluorophor and a quencher; and said method further comprising:
(i) when said oligomer is hybridized to said cDNA, detaching said fluorophor or said quencher from said oligomer using a polymerase having exonuclease activity during said PCR; and
(ii) detecting fluorescence from said fluorophor after its physical separation from said quencher, wherein said fluorescence is indicative of the presence of the cDNA.
2. The method of claim 1 , wherein at least 70% of said nucleotides are LNA nucleotide analogues.