The next-generation sequencing technology—beyond Sanger sequencing
With the development of science, the traditional Sanger sequencing has not fully meet the needs of research, organism model for genome sequencing and some non model organisms genome sequencing both need a new sequencing with lower cost, higher flux and fast rate. The Next-generation sequencing comes into being.
The core idea of the next-generation sequencing technology is Sequencing by Synthesis, that is, DNA sequencing is identified by capturing the end tags composed newly. DNA FLX Illumina/Solexa, Genome Analyzer system and Biosystems SOLID Roche/454 by capturing the end of the new synthesis. The existing technology platforms include Roche/454 FLX、Illumina/Solexa Genome Analyze and Applied Biosystems SOLID system. These three technologies have their own advantages. 454 FLX sequencing is longer, and its read length can reach 400bp; Solexa sequencing is the most popular, because not only the machine price is lower than the other two, and running costs are also low. Besides, in the same data volume, the cost is only 1/10 of 454 sequencing; SOLID sequencing’s accuracy is high, the accuracy of the original base data is more than 99.94%, and the accuracy of 15X coverage can reach 99.999%, which is currently the highest sequencing technology among the next-generation technology.
Solexa sequencing’s read length can reach 75bp. The size is much shorter than the traditional Sanger sequencing. But the advantage of Solexa sequencing is able to get massive data, and the price is low. By the same amount of data, Solexa sequencing is much cheaper than other sequencing. The length of 75bp is definitely not suitable for direct analysis. The reads of sequencing need to be mosaic before the actual use, which requires a strong biological information (bioinformation) analysis ability as a support.
Compared with the traditional sequencing technologies, the error rate of Solexa sequencing is relatively high, and the sequencing errors prone to distribute in the base of the reads. How to distinguish between the sequencing error and real DNA polymorphism is also a big problem.