Polymerase chain reaction fingerprints

Amplification of nucleic acids by polymerase chain reaction (PCR) and other methods and their applications

The in vitro replication of DNA, principally using the polymerase chain reaction (PCR), permits the amplification of defined sequences of DNA. By exponentially amplifying a target sequence, PCR significantly enhances the probability of detecting target gene sequences in complex mixtures of DNA. It also facilitates the cloning and sequencing of genes. Amplification of DNA by PCR and other newly developed methods has been applied in many areas of biological research, including molecular biology, biotechnology, and medicine, permitting studies that were not possible before. Nucleic acid amplification has added a new and revolutionary dimension to molecular biology. This review examines PCR and other in vitro nucleic acid amplification methodologies--examining the critical parameters and variations and their widespread applications--giving the strengths and limitations of these methodologies.

The polymerase chain reaction: miracle or mirage? A critical review of its uses and limitations in diagnosis and research

Since publication of the polymerase chain reaction (PCR) technique in 1985 (Saiki et al. Science 1985; 230: 1350-1354), there has been an explosion of reports on its use in medicine and science. We critically review its use both as a diagnostic technique and as a research tool, and show the pathologist how to evaluate PCR data and how to avoid the pitfalls of overinterpretation. We discuss the value of PCR in the characterization of genetic defects, prenatal diagnosis, carrier testing, HLA typing, detecting micro-organisms, identifying activated oncogenes, and in the characterization of leukaemias and lymphomas, and summarize the main applications in biomedical research.

cDNA library construction from small amounts of unfractionated RNA: association of cDNA synthesis with polymerase chain reaction amplification

We describe here a general and simple procedure for cDNA library construction making use of in vitro amplification of cDNA by polymerase chain reaction (PCR). The first-strand cDNA is synthesized from total RNA with a primer EcoRI-(dT)17 and oligo(dG) tailed. An oligonucleotide, EcoRI-BamHI-(dC)13, is used to prime the second-strand synthesis by the thermostable DNA polymerase of Thermus aquaticus. The double-stranded cDNA is then amplified directly by PCR. A study of the effect of the elongation time on the PCR products showed that a long extension time is necessary to overcome the size heterogeneity of the cDNA population. Starting from 1 microgram of total brain RNA, the products obtained ranged from 200 to more than 2000 bp. The presence of the myelin basic protein cDNA sequence was determined. A lambda gt10 library containing 2 x 10(6) clones was established with the amplified cDNA. No sequences originating from rRNA were detected by Southern blot analysis. The ability to produce representative cDNA libraries from minute amounts of total RNA by this protocol should have many applications to studies of gene expression in small amounts of tissues or cells.