What is NGS?
For many years now, DNA sequencing has been a vital tool for essential biological research. If we investigate the history of DNA sequencing, we can see that the first DNA sequences were acquired in the 1970s by researchers who used laborious methods based on two-dimensional chromatography. Since then, DNA sequencing has come a long way. Modern DNA sequencing, including Next Generation Sequencing (NGS), has played a key role in the sequencing of genomes or entire DNA sequences.
DNA sequencing is useful for several reasons. Comparing healthy DNA sequences to mutated sequences can help us to diagnose different diseases, including several cancers, characterize antibody repertoire, and it can also be used to guide a patient’s treatment. Having a fast way to sequence DNA allows for quicker and more individualized hospital care to be dispensed, and for more unknown organisms to be cataloged and identified.
DNA sequencing has become a key technology in many areas of biology and other sciences, including forensics, medicine, virology, biotechnology, and anthropology. If you want to know more about DNA sequencing and Next Generation Sequencing, then keep reading below: (Source: Paragon Genomics)
What is NGS?
NGS (or Next Generation Sequencing) is considered as the first of the “next-generation” sequencing technologies. These technologies enable RNA and DNA to be sequenced much quicker and much cheaper than traditional methods (such as the Sanger sequence). In fact, by using NGS, a complete human genome can be sequenced within 24 hours. As a result, the research in genomics and molecular biology has been revolutionized. However, although NGS has mostly overtaken traditional sequencing techniques in genomic research, this has not yet been translated into regular clinical practice.
What Information Can We Learn from NGS?
NGS gives us information about organisms in areas such as epidemiology, population genetics, organism identification, rare variant detection, genotyping, oncology diagnostics, gene environmental interaction, and gene editing confirmation.
How Does NGS Work?
All types of NGS work in a similar way:
- The first step is to obtain the genomic material, this can be either RNA or DNA. Fragmentation, purification, and amplification are used to do this.
- This material is then broken down into sections and split up into libraries. These libraries enable the sequencing process to take place. Library preparation includes things like adding adapters.
- Adapters are added so that the samples can be indexed. This allows numerous samples to be included in one sequencing run.
- If targeted NGS is being completed, then the next step is enrichment. During this step, scientists or researchers will select the area of interest.
- Illumina sequencing is then completed using sequencing by synthesis on a flow cell. This will generate between 100 and 300 base pair lengths (known as reads).
- The reads then go through quality control and are analyzed against a reference genome before being assessed for unusual characteristics.
NGS Vs Sanger Sequencing
In principle, the basics behind Sanger Sequencing and Next Generation Sequencing are remarkably similar. In both types of sequencing, DNA polymerase adds fluorescent nucleic acid onto a growing DNA template strand. The incorporated nucleic acid is then identified by its fluorescent tag.
The main difference between NGS sequencing and Sanger sequencing is sequencing volume. While the Sanger method only sequences one piece of DNA at a time, NGS sequences millions of pieces of DNA simultaneously each time. Not only that, but NGS also presents greater discovery power, it can uncover rare or novel variants with deep sequencing, and it offers more reliable results too.
As we mentioned above, unlike traditional methods, such as the Sanger sequencing method, NGS sequences thousands of gene fragments simultaneously. This means that compared to traditional methods, NGS is much quicker and cheaper.
The Main Benefits of Next Generation Sequencing
NGS has become a popular piece of technology in functional genomics and we can see why. There are several benefits to using Next Generation Sequencing to analyze DNA or RNA samples. Some examples include:
- Previous knowledge or genomic features of the genome is not needed in NGS.
- It provides single-nuclear resolution. This makes it possible to detect related genes and features, allelic gene variants, alternatively spliced transcripts, and single nucleotide polymorphisms.
- Compared to other methods, it requires smaller samples of RNA or DNA. In fact, nanograms of materials are sufficient.
- The reproducibility of it is much higher.
- It is faster and cheaper than other sequencing methods.
- It can identify novel pathogens – such as coronavirus.
- It can sequence whole genomes.
- It can study the human microbiome.
Next-Generation Sequencing is a sequencing method that facilitates sequencing profiling of everything from transcriptomes and genomes to DNA protein interactions. The basic next-generation sequencing process involves fragmenting RNA/DNA into numerous pieces, sequencing the libraries, adding adapters, and reassembling them to form a genetic sequence. NGS is not only accurate and fast, but it is also cheaper than most other sequencing technologies too.
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