PNA is DNA analog in which the phosphate backbone has been replaced by (2-aminoethyl) glycine unit that is linked to the nucleotide bases via the glycine amino nitrogen and methylenecarbonyl linkers. PNA can bind to complementary oligonucleotides by Watson-Crick base paring with high thermal stability and exhibit wide biological effects including modulating the function of DNA sequence specific binding protein and modulating the transcription and translation in vivo or in vitro. Many applications have been explored for PNA as a new kind of molecular biological tools. Despite its DNA(RNA)binding properties, recent progress has shown that PNA has potential for the development of gene-targeting pharmaceuticals.