Technological Background
During the process of DNA sequencing, the nucleic acid sequence – in other words, the order in which the nucleotides (letters) appear in the DNA – is determined. It also includes any methos and technology that determine the order in which adenine, guanine, cytosine, and thymine are arranged in a DNA molecule. The order of the nucleotides determines protein function and in case of mutations, the subsequent disease manifestation.
The first sequencing technology, known as Sanger, was developed in 1977 and is considered the first generation of sequencing technology. The next generation sequencing (NGS) was developed three decades later. NGS technologies provide massively parallel analysis, extremely high-throughput over many samples, and a lower cost as compared to the Sanger method. NGS methods differ primarily in the way DNA or RNA samples are processed, as well as the options available for analyzing the data. With the 3rd generation sequencing (Single Molecule Real-Time (SMRT) seq, Oxford nanopore seq, and Helicos seq), the process is even faster and cheaper.
It is possible to sequence the genome (whole genome sequencing, WGS), only the protein-coding region (whole exome sequencing, WES), selected fragments (targeted sequencing, abbreviated to TS), or candidate methylation sequencing (CGS).
What is solves
As a result of sequencing, researchers can ask virtually any question related to a genome, transcriptome, or epigenome of any organism. In addition to diagnosing different diseases, such as cancer, treatment planning can be based on DNA sequence comparisons.
Polygenic risk scores, which are single-value estimates of an individual’s genetic liability to a condition, are calculated by identifying genetic alterations in the genome. The ability to sequence DNA quickly allows for faster and more individualized medical care, as well as the identification of more organisms.
In this way, NGS technology is indeed egalitarian in that it allows both small and large research groups to answer many different questions in the fields of genetics and biology, including those in medicine, agriculture, forensics, virology, microbiology, and marine and plant biology.