Evolution of Sequencing technologies!!
- September 9, 2017
- Posted by: rasa
- Category: Next Generation Sequencing
With the advancements in Sanger sequencing continuing, it has become an absolute key to enigmatic method in identification of closed closets in the gene pool. The major drawback even with the advance Sanger sequencers was the cost per base and problems related to cloning and sequencing of regions containing repetitive sequences. But with the advancement in molecular genetics, new age sequencing was due to come. Also the Human Genome Project made a tremendous financial impact on research community creating an urge-urgent need for alternative high throughput methods of sequencing. Thus the idea of massively parallel sequencing came into existence using which short strands of genetic material can be sequenced over recurring multiples Thus higher number of amplicon’s generated provides exponentially larger dataset for analysis. Eventually Next Generation Sequencing (NGS) technology has opened an entire spectrum of genomic alterations for the genetic analysis of complex traits.
Number of technologies offering a better faster and more accurate sequencing has come up thereby drastically decreasing the cost of sequencing. Techniques such as AB SOLiD, Illumina Solexa Genome Analyzer, Roche 454 have now become common place. Advancements in sequencing technologies accelerate the rate of deep research making the core data available for understanding the concepts of identity. With the evolution in Sanger sequencing technology more of sequencing studies began. Thus the need of faster sequencing methods became requisite.
The following table gives a summary and the comparison of the next generation sequencing methods along with sanger method. It also states the applications of these sequencing techniques. By looking at the table one can get a fair idea the benefits the NGS methods have in sequencing the genomic data.
Mechanism, Advantages, Disadvantages
|Sequencer/ Attributes||Roche 454||Illumina||AB SOLiD v4||Sanger method|
|Sequencing mechanism||Pyrosequencing||Sequencing by synthesis with reversible termination||Ligation and two base coding||Dideoxy chain termination|
|Read Length||700bp||50SE, 50PE, 101PE||50+35bp, 50+50bp||400~900bp|
|Accuracy||99.9%||98% (100PE)||99.94% (Raw data)||99.999%|
|Output data/ run||0.7 Gb (700Mb)||600Gb||120Gb||1.8~84Kb|
|Time/ run||24 hrs||3~10 days||7 days- SE
14 days- PE
|Advantage||Read length, fast||High throughput||Accuracy||High quality, long read length|
|Disadvantage||Error base with polybase more than 6||Short read assembly||Short read assembly||High cost low throughput|
Application of sequencers
|High GC sample||Yes||Yes||Yes|