DNA sequencing, technique used to determine the nucleotide sequence of DNA (deoxyribonucleic acid). The nucleotide sequence is the most fundamental level of knowledge of a gene or genome. It is the blueprint that contains the instructions for building an organism, and no understanding of genetic function or evolution could be complete without obtaining this information.

First-Generation Sequencing Technology: So-called first-generation sequencing technologies, which emerged in the 1970s, included the Maxam-Gilbert method, discovered by and named for American molecular biologists Allan M. Maxam and Walter Gilbert, and the Sanger method (or dideoxy method), discovered by English biochemist Frederick Sanger. In the Sanger method, which became the more commonly employed of the two approaches, DNA chains were synthesized on a template strand, but chain growth was stopped when one of four possible dideoxy nucleotides, which lack a 3’ hydroxyl group, became incorporated, thereby preventing the addition of another nucleotide. A population of nested, truncated DNA molecules was produced that represented each of the sites of that particular nucleotide in the template DNA. The molecules were separated according to size in a procedure called electrophoresis, and the inferred nucleotide sequence was deduced by a computer. Later, the method was performed by using automated sequencing machines, in which the truncated DNA molecules, labeled with fluorescent tags, were separated by size within thin glass capillaries and detected by laser excitation.

Next-Generation Sequencing Technology: Next-generation (massively parallel or second-generation) sequencing technologies have largely supplanted first-generation technologies. These newer approaches enable many DNA fragments (sometimes on the order of millions of fragments) to be sequenced at one time and are more cost-efficient and much faster than first-generation technologies. The utility of next-generation technologies was improved significantly by advances in bioinformatics that allowed for increased data storage and facilitated the analysis and manipulation of very large data sets, often in the gigabase range (1 gigabase = 1,000,000,000 base pairs of DNA).

Regards,

Angelina Matthew,

Managing Editor,

Journal of Genetics and Genomes

Email Id: genetics@scholarlypub.com