What is Next-Generation DNA Sequencing?


DNA sequencing is the process of determining the sequence of nucleotides in a section of DNA. The first commercialised method of DNA sequencing was Sanger sequencing.

Next-generation sequencing (NGS), also known as high-throughput sequencing, is the catch-all term used to describe a number of different modern sequencing technologies. These technologies allow for sequencing of DNA and RNA much more quickly and cheaply than the previously used Sanger sequencing, and as such revolutionised the study of genomics and molecular biology. Such technologies include:

Illumina (Solexa) sequencing

Illumina sequencing works by simultaneously identifying DNA bases, as each base emits a unique fluorescent signal, and adding them to a nucleic acid chain.

Roche 454 sequencing

This method is based on pyrosequencing, a technique which detects pyrophosphate release, again using fluorescence, after nucleotides are incorporated by polymerase to a new strand of DNA.

Ion Torrent: Proton / PGM sequencing

Ion Torrent sequencing measures the direct release of H+ (protons) from the incorporation of individual bases by DNA polymerase and therefore differs from the previous two methods as it does not measure light.

Continue this introduction to NGS

The next few pages provide step-by-step explanations of how each of these NGS technologies work, starting with Illumina sequencing.