Snp Detection, Pna Probes, Hybridization Probes, Ionic Strength, Hybrid Duplexes, Magnetic Beads, Specific Allele, Matrix Solution

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Your Ad Here	SNP Detection Using PNA Probes. Peptide nucleic acids (PNAs) are being used for a variety of purposes, including their use as hybridization probes .They are actually preferred over DNA/RNA probes, due to (i) their ability to hybridize under low ionic strength, (ii) the increased hybridization specificity for complementary DNA, and (iii) the increased thermal stability they provide to the hybrid duplexes formed. PNAs can also be more easily analysed by MALDI-TOF MS, since peptide back bone does not fragment during MALDI.
For SNP analysis, two allele specific PNA probes, one for each SNP allele are annealed to biotinylated single-stranded PCR products that are immobilized on streptavidin coated magnetic beads. Aster annealing, the breads are stringently washed so that only perfectly matched probes remain hybridized. The entire bead solution is then spotted on MALDI probe tip and acidic matrix solution is added to the beads, which dissociates the PNA probe from immobilized DNA. The mixture is then irradiated so that PNA is desorbed, ionized and detected by its mass; each unequally mass-labelled PNA probe detected ccrresponds to a specific allele.
(a) Schematic Diagram of Steps Involved in the Mass-Spectrometric Analysis of Peptide Nucleic-Acid Hybridization Probes (b) Composite Mass Spectra Representing Four Hypothetical Wild Types WT1 to Wt4 and a variant (VAR) Allele for a unique Single-nucleotide Polymorphism; in this case Sampel Heterozygous for WT4 allele and Homozygous for the other three WT alleles.	Your Ad Here