All Illumina sequencing systems use our proven sequencing by synthesis (SBS) technology. SBS is the most widely adopted next-generation sequencing (NGS) technology, producing more than 90% of global sequencing data.* SBS delivers highly accurate base-by-base sequencing and robust performance across the genome.
Several Illumina instruments use a recent evolution of SBS technology known as 2-channel SBS. This method enables faster data generation with the same high data accuracy as the original Illumina 4-channel SBS technology.
The 2-channel SBS method requires only 2 images per cycle, instead of 4 (Figure 1). This accelerates sequencing and data processing times, while delivering the same quality and accuracy that sets Illumina systems apart. These advances make 2-channel SBS an affordable solution, enabling NGS to become an everyday tool in laboratories worldwide.
Rather than using a separate dye for each base, 2-channel SBS simplifies nucleotide detection by using two fluorescent dyes and two images to determine all four base calls. Images are taken of each DNA cluster using red and green wavelength filter bands.
Clusters seen in red or green images are interpreted as C and T bases, respectively. Clusters observed in both red and green images are flagged as A bases (appearing as yellow clusters), while unlabeled clusters are identified as G bases.
While SBS chemistry forms the foundation of all Illumina sequencers, the optical systems have evolved to include multiple detection methods. Learn more about how 2-channel SBS compares to 1-channel and 4-channel SBS, and view quality score data.Read Technical Note
2-channel chemistry uses two different fluorescent dyes. In contrast, the original 4-channel chemistry uses a mixture of nucleotides labeled with four different fluorescent dyes, while 1-channel chemistry uses only one dye. The images are processed by image analysis software to determine nucleotide identity.
The MiniSeq System leverages 2-channel SBS to offer a small, affordable benchtop sequencer. It supports a wide range of applications, from targeted DNA and RNA sequencing to tumor profiling studies, small RNA discovery, and more.
The NextSeq 550 System delivers speed and simplicity for everyday genomics, leveraging 2-channel SBS to offer efficient sequencing and data generation. This benchtop sequencer supports whole-transcriptome, exome, and targeted resequencing studies.
The NovaSeq 6000 System offers scalable throughput and flexibility for virtually any genome, sequencing method, and scale of project.
1-channel SBS couples sequencing by synthesis chemistry with complementary metal-oxide semiconductor (CMOS) technology. While it uses the same base-calling architecture as 2-channel SBS, the 1-channel method supports lower instrument costs and the convenience of a small instrument footprint, all while maintaining high accuracy. Our smallest sequencer, the iSeq 100 System, uses 1-channel SBS.
* Data calculations on file. Illumina, Inc. 2015.