DNA sequencing is the process of determining the nucleotide sequence of a DNA strand. It involves techniques which can obtain information on the order of the four nucleotide bases: adenine, guanine, cytosine,and thymine in DNA. Before sequencing, there are protocols which must be followed toobtain pure target DNA. This includes extraction of the DNA from particular sources, purification of the DNA, amplification by PCR may be necessary. Library preparation is required in the case of next-generation sequencing methods.

 

Basic DNA sequencing methods include the Sangers method or chain termination method, and the Maxam-Gilbert sequencing technique. Advanced sequencing methods were then developed, such as shotgun sequencing for large DNA fragments. Furthermore, high-throughput sequencing is available which can run multiple sequences in parallel to display variations in a genome. Examples of these includeMassively parallel signature sequencing (MPSS), Polony sequencing, 454 pyrosequencing, SOLiD sequencing, Single-molecule real-time (SMRT) sequencing etc.

 

These sequencing methods require multiple reagents and biochemicals, which conveniently are bundled into kits for quick and easy use.