NEXT GENERATION SEQUENCING

 

What is next-generation sequencing?

Next-generation sequencing (NGS) is a method of DNA sequencing that has revolutionized the field of genomics. NGS technology allows for the rapid and cost-effective sequencing of large amounts of DNA, making it possible to sequence entire genomes in a fraction of the time and cost of traditional sequencing methods.

Principle

NGS technology is based on the principle of parallel sequencing, where millions of DNA fragments are simultaneously sequenced in a single reaction. This is in contrast to traditional Sanger sequencing, which sequences one fragment at a time. NGS technology has been used to sequence many different types of organisms, including bacteria, viruses, fungi, plants, and animals, including humans.

Types of next-generation sequencing

There are several different NGS platforms available, each with its own unique advantages and limitations. The most widely used platforms include Illumina, PacBio, and Oxford Nanopore.

• Illumina is the most widely used NGS platform and is known for its high throughput and low cost. The Illumina platform uses a technique called sequencing by synthesis, where DNA is first fragmented and then attached to a solid surface. The four nucleotides (A, C, G, T) are then added one at a time, and the incorporation of each nucleotide is detected by a fluorescent signal.
• PacBio is another NGS platform that is known for its long read lengths and high accuracy. The PacBio platform uses a technique called single molecule, real-time sequencing, where DNA is sequenced in real-time as it is passed through a zero-mode waveguide.
• Oxford Nanopore is a newer NGS platform that is known for its long read lengths and real-time sequencing capabilities. The Oxford Nanopore platform uses a technique called nanopore sequencing, where DNA is passed through a pore and the changes in the electrical current are used to determine the identity of each nucleotide.
• Pyrosequencing is a type of next-generation sequencing technology that utilizes a phenomenon known as “sequencing by synthesis.” In this method, DNA polymerase is used to add nucleotides one at a time to a growing strand of DNA, and the incorporation of each nucleotide is detected by the release of a light signal. This light signal is then used to determine the identity of the nucleotide that was added. Pyrosequencing allows for real-time sequencing, high accuracy, and long read lengths, making it useful for applications such as detecting mutations, resolving complex genomic regions, and characterizing microbial communities.
• Ion Torrent Sequencing: This technology is based on the detection of hydrogen ions that are released during the incorporation of nucleotides by polymerase enzymes.

Applications of next-generation sequencing

NGS technology has many applications in the field of genomics, including the study of genetic disease, the identification of cancer-causing mutations, and the discovery of new drug targets. NGS technology has also been used in the study of evolution and population genetics, as well as in the identification of pathogens and the development of new diagnostic tests.
NGS technology has also been used in the field of personalized medicine, where the patient’s genome is sequenced to determine the best treatment options. By identifying the specific genetic mutations that are present in a patient’s tumor, doctors can choose the most effective treatment, such as targeted therapies or immunotherapies.
NGS technology has also been used in the field of precision agriculture, where the genomes of crops are sequenced to identify genes that are associated with important traits such as drought tolerance or pest resistance. This information can be used to develop new crop varieties that are better adapted to the changing climate.
In conclusion, next-generation sequencing technology has revolutionized the field of genomics, making it possible to sequence large amounts of DNA in a fraction of the time and cost of traditional methods. NGS technology has many applications in the study of genetic diseases, personalized medicine, and precision agriculture. As the cost of NGS continues to decrease, it is expected that this technology will continue to have a significant impact on many areas of science and medicine.