What is DNA sequencing?
The method by which the precise order of nucleotides is determined within a DNA molecule in a strand of DNA is known as DNA sequencing. Any technology or method used during DNA processing is for the purpose of determining the order of four bases of nucleotides namely adenine, guanine, cytosine and thymine in any DNA sample.DNA sequencing does not only helps in in sequencing of individual genes but also assists in determining the sequences in large genetic regions, entire genomes and full chromosomes of any organism.
Methods of DNA sequencing
The methods of DNA sequencing have recently being simplified and developed thereby eliminating the problems relating to the difficulty and indirect determination of sequences as were faced earlier. Back then the methods of DNA sequencing were cumbersome owing to which the DNA was initially required to be converted into a RNA and then the further procedure of limited RNA sequencing was carried out. Under the functionality of these methods only shorter DNA sequences were able to be determined. By making use these, Walter Gilbert and Alan Maxam determined that the Lac operator is a twenty seven bp long sequence, at Harvard University.
There are seven methods in all that can be used for the purpose of practicing DNA sequencing-
- Sanger’s method
- Hybridisation method
- Pal Nyren’s method
- Maxam and Gilbert method
- Automatic DNA sequencer
- Capillary gel electrophoresis and
- Slab gel sequencing systems
Sanger’s method of DNA sequencing was the first method that was introduced in the year 1975 by Sanger and Coulson and was popularly known as plus minus sequencing. This method of DNA sequencing was not much advanced and developed and was thereby cumbersome. It was not very efficient.
Applications of DNA sequencing
DNA sequencing is largely used for biological and medical research and discovery purposes. The discovery and advent of rapid DNA sequencing methods have greatly fuelled its applications. Lately the knowledge of DNA sequences has become of vital importance for the basic researches in biological works. Moreover a number of applied fields including biotechnology, virology, biological systematic, forensic biology and medical diagnosis are making use of DNA Sequencing at a large too.
Furthermore DNA sequencing is also considered to be one of the most efficient ways of determining the sequence of proteins or RNA via their open reading frames. The advancements and development in the methods of DNA sequencing have largely contributed in expanding the scope of biological research. While the DNA sequencing changed from plus minus sequencing to pyro sequencing in the last twenty years approximately. It has simultaneously leaded to the progress in biology from molecular biology to genomics.