The macro molecule Deoxy ribonucleic acid (DNA) is of interest for all biology researchers due to the fact that it is the genetic material for all eukaryotic organisms. The genetic material DNA during replication accumulates variations and mutations, which might be associated with diseases. The identification of mutations responsible for diseases is currently done for very well established disease biomarker genes with PCR techniques. To analyze the complete genome of an organism more robust sequencing technique is the need of the moment.
The first available method of rapid DNA sequencing was developed by Sanger and was known as Sanger method. This method was made automated to sequence whole genome and was considered as first generation sequencing. Using Sanger method, human genome was first sequenced which took long time and nearly million of dollars were spent involving many laboratories. The further methods developed to overcome the time required for whole genome sequencing and cost of sequencing are termed as Next Generation Sequencing (NGS). NGS technique is a kind of high throughput data DNA sequencing. NGS technique integrates various strategies of sequencing, genome assembly and alignment to fasten the sequencing procedure and to reduce the error in sequencing. Using NGS technique, the whole genome can be sequence in few days. The development of NGS now shadowed the earlier most used techniques such as automated Sanger method, microarrays, etc. The main advantage of NGS is its ability to generate huge data cheaply in less time. The sequencing of whole genome in short duration has lead to the possible of comparing different organism and also different individual of same species. The 1000 genome project relays heavily on NGS. NGS technology aims helping mankind by sequencing individual genome at very affordable price with high accuracy that can be used in Disease diagnosis and treatment for individuals termed as personalized medicine.
NGS technique consists of three phases, first one as template preparation, second sequencing and imaging and third as analysis of data generated. In the template phase, Genome of the organism is amplified and the fragments are allowed to bind to primers on solid platforms. The bound single DNA strands acts as template and helps extend the bound primers. The template single strands are released in dissociation cycle allowing only bound single stranded DNA on solid surfaces having replica of genomic sequences. The next phase is the sequencing and imaging, where in the dye labeled nucleotides are detected with imaging software and the nucleotide positions are sequenced based on the incorporated labeled nucleotides. The last step in NGS is alignment and assembly of sequenced nucleotides to the reference genome. In each step of NGS, there are several limitations and various techniques are applied in order to overcome them. More researches are done in developing the NGS data analysis platforms; algorithms for data assembly and alignment and software for imaging.
NGS technique can be used to identify variations such Single Nucleotide Polymorphisms (SNP), Copy Number Variations (CNS) such as Deletions and Duplications, Point mutations, translocations and Inversions. Further NGS analysis can be utilized in prenatal diagnosis to detect any abnormalities in the fetus. NGS can also be used in re-sequencing of selected list of genes that are associated with disease/ disorder, which will help to suggest appropriate medical treatment. NGS technique can be utilized in agriculture to understand the genomics of economical important crops and also in veterinary for sequencing domesticated animals to improve the animal breed.
The fascinating terminology NGS has tremendous applications in human health science. The whole genome sequencing of any organism with less time and price through NGS allowed higher bioinformatics research in the area of comparative genomics. NGS can be utilized to find variation in the genome of individual patients and finding causes such as disease symptoms, drug adverse effects, etc., which will help to give better treatment. NGS has many applications in the field of evolutionary biology, agriculture, microbiology and other related fields. Apart from health science, many job opportunities are developed in the field of data management and handling, storage, data analysis and algorithm development since NGS results in the generation of voluminous data. We hope that NGS research booms in the coming years giving job opportunities for many people.
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