What is Polymerase Chain Reactionin genetics?

A great advance in sequencing and cloning DNA is the polymerase chain reaction, devised by the American biochemist Kary Mullis in 1984. By this technique, millions of copies of a DNA sequence can be produced in a medium containing appropriate nucleotides and enzymes. As the name suggests, newly replicated DNA strands serve as templates to build additional copies.

Polymerase chain reaction, or PCR technology, is an important tool in gene sequencing, the determination of the order of nucleotides in a DNA strand, because it is possible to characterize as little as a single molecule of DNA. It is useful in medical forensics, or medical detective work, since DNA "fingerprints" are unique to each individual, and tiny quantities of tissue containing DNA may be left at a crime scene. PCR technology is also invaluable in early diagnosing of diseases where organisms may be present in such small quantities that they have not yet caused detectable antibody production.