Polymerase Chain Reaction (PCR)

• The molecular technique known as Polymerase Chain Reaction produces more than a billion copies of minute amounts of target DNA in a short time. One common application of PCR is the amplification of DNA from tissue, hair, blood or other body fluids to solve crimes. Amplification is often the first step in sequencing and cloning.
  
  

Sequencing

• Sequencing determines the order of nucleotide bases in a gene, and provides genetic information about the DNA. Sequencing is useful in identifying changes or mutations in DNA that may be the cause of diseases. One of the most successful applications of molecular techniques has been the sequencing of the human genome. Comparing sequences from samples of unknown origin can also help to determine the relationship between organisms.
  
  

DNA Cloning

• Molecular techniques have enabled recombinant DNA cloning or genetic engineering, a process in which the basic inherent characteristics of an organism are replaced by desired ones. DNA cloning involves the isolation of DNA, which is inserted into a bacterial plasmid. This results in the mass production of the cloned DNA by the multiplying bacteria. Insulin produced by recombinant DNA technology has been commercially available since 1982.
  
  

DNA Fingerprinting

• There are certain regions in the human genome that are unique to an individual and can be determined by DNA fingerprinting. Scientists use PCR to amplify samples for 13 of these regions called Short Tandem Repeats. The PCR products separate according to their size by gel electrophoresis, with the smallest fragments moving faster than the bigger ones. Since the STR of no two individuals are alike, forensic scientists use this technique to solve crimes.