Four Generations of Sequencing- Is it Ready for the Clinic Yet?

Srilakshmi Srinivasan,Jyotsna Batra

doi:10.4172/2469-9853.1000107

Abstract

Next-generation sequencing techniques have revolutionized over the last decade providing researchers with low cost, high-throughput alternatives compared to the traditional Sanger sequencing methods. These sequencing techniques have rapidly evolved from first-generation to fourth-generation with very broad applications such as unraveling the complexity of the genome, in terms of genetic variations, and having a high impact on the biological field. In this review, we discuss the transition of sequencing from the second-generation to the third- and fourthgenerations, and describe some of their novel biological applications. With the advancement in technology, the earlier challenges of minimal size of the instrument, flexibility of throughput, ease of data analysis and short run times are being addressed. However, the need for prospective analysis and effectiveness to test whether the knowledge of any given new variants identified has an effect on clinical outcome may need improvement.

Highlights

The past decade has experienced advancement in the study of genetics, molecular diagnostics and personal medicine through the discovery and improvement of next-generation sequencing (NGS) techniques
Continuous improvement in NGS technologies imply, that the whole genome can be sequenced faster, easier and with a higher accuracy since the advent of Sanger sequencing in 1977. These new techniques are highly poised to disclose the complexity between genetic variants such as single nucleotide polymorphisms (SNPs), copy number variations (CNVs), structural variants, including gene fusions with diseases
In 2008 the Roche 454 was replaced by the 454 GS FLX Titanium system which is capable of generating 700 megabase (Mb) of sequence in 700 bp reads in a 23 hr. run with an accuracy of 99.9% after filtering [10]

Summary

Introduction

The past decade has experienced advancement in the study of genetics, molecular diagnostics and personal medicine through the discovery and improvement of next-generation sequencing (NGS) techniques. Continuous improvement in NGS technologies imply, that the whole genome can be sequenced faster, easier and with a higher accuracy since the advent of Sanger sequencing in 1977 These new techniques are highly poised to disclose the complexity between genetic variants such as single nucleotide polymorphisms (SNPs), copy number variations (CNVs), structural variants, including gene fusions with diseases. NGS enables worldwide collaborative efforts like the International Genome Consortium (ICGC) [3] and the Cancer Genome Atlas (TCGA) projects [4] to catalogue many thousands of cancer genomes for several disease types Research discoveries from these projects have been published and have been non-trivial in improving our knowledge of disease pathogenesis thereby bridging the molecular pathology and personalized medicine [5]. The technique has the disadvantage of having high reagent costs and high error rates for poly-bases longer than 6 bp (Table 1)

Method

Findings

Conclusion