If you follow healthcare and medical news, you’ve heard the term next generation sequencing or NGS. It is a concept that can be confusing, especially since technology continues to evolve. To better understand NGS, you must know a little about its history.
What Is NGS?
Let’s start with the basics. What is NGS? Next generation sequencing is a high-throughput technology that allows scientists to figure out the code sequences of DNA. Deoxyribonucleic acid or DNA is the basis of life. It is a double-helix code that determines who you are and what you will look like.
These two strands of DNA are made up of smaller units called nucleotides. Each nucleotide contains just four nucleobases:
- Cytosine
- Guanine
- Adenine
- Thymine
The organization of these bases determines if you will have blue eyes or brown, if you will be an artist or a science nerd, and if you will be tall or short. The bases can also be at the heart of disease processes. For example, a simple mutation in the organization of one or more nucleobases can determine if you will develop cancer, have sickle cell anemia or be at risk for heart disease.
The problem for scientists has always been how to figure out DNA code. Those four nucleobases make up a lot of possibilities, and it has always been a struggle to figure them out. Finally, two decades after the discovery of DNA, Frederick Sanger developed a way to decode it.
Sanger Sequencing
Sanger sequencing was one of the first practical ways to sequence the nucleotides in DNA and is still used today. With Sanger sequencing, scientists can determine the code of different nucleotides, one unit at a time. It can be done manually or automatically using technology.
Although Sanger sequencing is an effective way to sequence DNA, it is slow and costly. That made its use very limiting. Scientists needed a way to speed up the process and bring down the cost. That led to the advent of next generation sequencing.
How does NGS Work?
Unlike Sanger sequencing, NGS can sequence many nucleotides at once. Sequencing a full human genome quickly and accurately with this method is possible.
NGS got its start in 2003 with the Human Genome Project. Through NGS, scientists can fragment DNA and RNA into different pieces, sequence them, and then put them back together. In addition, this technology can sequence millions of fragments at once in a parallel fashion.
There are three primary steps to NGS:
Library preparation – Library preparation is one of the most critical steps to NGS. It involves preparing the DNA or RNA samples to work in the sequencing technology.
Sequencing – Sequencing involves loading what is now fragmented sections of the code, or libraries, into the sequencer using a flow cell. Then, the technology amplifies that process to allow millions of copies of a single DNA strand.
Data analysis – During the data analysis phase of next generation sequencing, the technology identifies the nucleotides and their base codes.
NGS continues to evolve and, today is helping scientists better understand how to treat conditions that were always believed to be untreatable.
