POLYMERASE CHAIN-REACTION IN GASTROENTEROLOGY

Polymerase chain reaction (PCR) has had a major impact on molecular bi ology and is beginning to change our perception of certain disease pro cesses and diagnostic tests. PCR allows the identification and amplifi cation of very rare nucleic acid sequences. This is resulting in our i dentification of previously elusive infectious agents and of mutations that may affect the course of viral infections or carcinogenesis. PCR can now analyze the expression of genes from single cells or single m olecules of nucleic acid from a sample source. Once pitfalls in contam ination are overcome and more probes for genes of biological and medic al interest become available, PCR technology will become universally e mployed in the clinical laboratory.