Illuminas operating system

[Kultamuna2]

Hi! Can anyone tell me, why Illumina's sequencing systems have two lasers (or in NovaSeq, four lasers)? I am a bit confused how the system works. Do those lasers change constantly wavelengths to identify all the four bases, or do they stay in a specific wavelength? Thanks already in advance!

[kc3228]

The two lasers are red and green. Red is C, green is T. A is labeled with both red and green, so shows up in both. G is dark (unlabeled), so a lack of signal is interpreted as G.

[GW_OK]

The lasers excite at fixed wavelengths. The fluorophores emit at different respective wavelengths. The example given by kc3228 is for the dual color chemistries of the NextSeq and NovaSeq. The MiniSeq, Miseq, and Hiseq systems use a 4 color chemistry.

[misterc]

MiniSeq is essentially a single camera NextSeq, so 2-color SBS there (not 4).

[GW_OK]

Good to know.

I suppose the iSeq is single color, since it's got the CMOS in the flowcell.

[GenoMax]

iSeq is one-dye, two-chemistry and two-images per sequencing cycle. See page 3.

[kmcarr]

Here's another doc from Illumina which also describes the CMOS flow cell and compares the various detection chemistries (1, 2, 4 color) used by Illumina.

[GenoMax]

Nice find @kmcarr. Thanks for posting.