The use of peptide nucleic acids for in situ identification of human chromosomes

The peptide nucleic acids (PNAs) constitute a remarkable new class of synthetic nucleic acid analogues, based on their 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 physicochemical properties of PNAs have led to the development of a large variety of research and diagnostic assays, including antigene and antisense therapy, genome mapping, and mutation detection. Over the past few years, PNAs have been shown to be powerful tools 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, and spermatozoa, as well as on isolated oocytes and blastomeres. Multicolor PNA protocols have been described for the identification of several human chromosomes, indicating that PNAs could become a powerful complement to FISH for in situ chromosomal investigation.