Peptide Nucleic Acids (PNAs) as Diagnostic Devices for Genetic and Cytogenetic Analysis

The peptide nucleic acids (PNAs) constitute a remarkable new class of synthetic nucleic acids analogs, based on peptide-like backbone. This structure gives to PNAs the capacity to hybridize with high affinity and specificity to complementary RNA and DNA sequences, and a great resistance to nucleases and proteinases. Originally conceived as ligands for the study of double stranded DNA, the unique physico-chemical properties of PNAs have led to the development of a large variety of research and diagnostic assays in the field of genetics, including genome mapping and mutation detection. Over the last few years, the use of PNAs has also proven its powerful usefulness in cytogenetics for the rapid in situ identification of human chromosomes and the detection of aneuploidies. Recent studies have reported the successful use of chromosome-specific PNA probes on human lymphocytes, amniocytes, spermatozoa as well as on isolated oocytes and blastomeres. Multicolor peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) protocols have been described for the identification of several human chromosomes, indicating that PNAs could become a powerful tool for in situ chromosomal investigation.