Difference Between NGS and WGS

The key difference between NGS and WGS is that next-generation sequencing (NGS) is a massively parallel second-generation sequencing technology that is high throughput, low cost, and speedy, while whole-genome sequencing (WGS) is a comprehensive method of analyzing the entire genomic DNA of a cell at a single time by using sequencing techniques such as Sanger sequencing, shotgun approach or high throughput NGS sequencing.

In the last few decades, the understanding of the genome of humans and other animals has increased massively due to the discovery of rapid sequencing techniques and bioinformatics tools. Conventional sequencing techniques such as Sanger sequencing had their limitations, which called for the development of new rapid sequencing methods such as next-generation sequencing (NGS) and nanopore sequencing. The whole-genome sequencing (WGS) technique is a recent approach that is already used in many genomic research projects, such as 100,000 genomic project by Genomic England, UK. So, NGS and WGS are two sequencing methods that are currently incorporating in many genomic projects.

CONTENTS

1. Overview and Key Difference
2. What is NGS 
3. What is WGS
4. Similarities – NGS and WGS
5. NGS vs WGS in Tabular Form
6. Summary – NGS vs WGS

What is NGS?

NGS (next-generation sequencing) is a massively parallel second-generation sequencing technology that is high throughput, low cost, and speedy. There is no precise definition for next-generation sequencing. But we can clearly distinguish it from conventional capillary-based sequencing techniques. Next-generation sequencing allows the sequencing of a DNA molecule with a total size larger than 1 million base pairs in a single experiment. It offers unprecedented speed and high throughput options, such as allowing the sequencing of DNA of multiple individuals at the same time. This is achieved by miniaturizing the volume of individual sequencing reactions. Moreover, this also limits the size of the instruments and minimizes the cost of reagents per reaction.

NGS is a short-read sequencing method that has already revolutionized the biological research field. Furthermore, NGS is applied in various areas like de novo genome sequencing, whole-genome sequencing, transcriptome analysis, small RNA and micro RNA sequencing, targeted resequencing, and whole-exome sequencing.

What is WGS?

WGS (whole-genome sequencing) is a comprehensive method of analyzing the entire genomic DNA of a cell at a single time by using sequencing techniques such as Sanger sequencing, shotgun approach, or high throughput NGS sequencing. It is also known as full genome sequencing or complete genome sequencing. Whole-genome sequencing entails the sequencing all of an organism’s chromosomal DNA as well as DNA in mitochondria, and for plants, the DNA in the chloroplast at a single time. WGS enables scientists to read the exact sequence of all the letters that make up the complete set of DNA. WGS using NGS platform is expected to revolutionize clinical setup.

Whole-genome sequencing was introduced to clinical care in 2014. Furthermore, the application of WGS involves gene sequencing at the SNP level to pinpoint functional variants in association studies, therapeutic intervention in personalized medicine, evolutionary biology, comparative genomic analysis, mutations and rearrangements studies, rare variant association studies, and predicting disease susceptibility and drug response.

What are the Similarities Between NGS and WGS?

• NGS and WGS are two sequencing techniques.
• Both techniques either sequence DNA or RNA.
• These techniques are new and reliable.
• They are both used in diagnosing diseases and drugs discovery.

What is the Difference Between NGS and WGS?

NGS is a massively parallel second-generation sequencing technology that is high throughput, low cost, and speedy, while WGS is a comprehensive method of analyzing the entire genomic DNA of a cell at a single time by using sequencing techniques such as Sanger sequencing, shotgun approach or high throughput NGS sequencing. So, this is the key difference between NGS and WGS. Furthermore, NGS consists of only second-generation sequencing methods while WGS consists of first, second, and third generations sequencing methods.

The following table presents the differences between and NGS and WGS in tabular form for side by side comparison.

Summary – NGS vs WGS

In the past decades, different sequencing techniques have routinely been applied in contemporary molecular research. And even they are very powerful tools for many clinical applications. NGS and WGS are two sequencing methods that are currently incorporating in many genomic projects.   NGS is a second-generation sequencing technology that is high throughput, low cost, and speedy. On the other hand, WGS is a method of analyzing the entire genomic DNA or full genomic DNA of a cell at a single time by using sequencing techniques such as Sanger sequencing, shotgun approach, or high throughput NGS sequencing. So, this is the summary of the difference between NGS and WGS.

Reference:

1. Behjati, Sam, and Patrick S Tarpey. “What Is next Generation Sequencing?” Archives of Disease in Childhood. Education and Practice Edition, BMJ Publishing Group.
2. “Whole Genome Sequencing.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “2nd Generation Sequencing” By Chandra Shekhar Pareek, Rafal Smoczynski, and Andrzej Tretyn – Journal of Applied Genetics – Volume 52 – Issue 4 (CC BY-SA 3.0) via Commons Wikimedia
2. “Whole genome shotgun sequencing versus Hierarchical shotgun sequencing” By Commins, J., Toft, C., Fares, M. A. – “Computational Biology Methods and Their Application to the Comparative Genomics of Endocellular Symbiotic Bacteria of Insects” Biol. Procedures Online (2009). Accessed via SpringerImages. (CC BY-SA 2.5) via Commons Wikimedia